This very deep Chandra observation of the galaxy cluster Abell 2052 reveals detailed structure in the inner region, including bubbles evacuated by the radio lobes, compressed bubble rims, filaments, and loops. Two concentric shocks are seen, with a temperature rise measured for the inner shock. On larger scales, a spiral feature is detected, likely resulting from sloshing gas initiated by a previous merger. Initial evidence is also presented for previously unseen outer bubbles related to earlier black hole outbursts.
This document summarizes radio observations of the Type IIb supernova SN 2001ig made with the Australia Telescope Compact Array and Very Large Array over 700 days. The observations found periodic deviations from the standard model of radio light curves that are consistent with recurring density modulations in the circumstellar medium with a period of around 150 days. This provides evidence that the progenitor was a Wolf-Rayet star in a binary system with an eccentric 100 day orbit, causing regular build-up of circumstellar material. Such binary systems are thought to produce Type Ib/c supernovae through envelope stripping, linking these events to Type IIb supernovae.
The absorption spectrum of cerium-doped calcium fluoride (CaF2:Ce2+) was observed at several temperatures. At low temperatures, the spectrum consists of transitions from the ground state to levels of the 4f configuration. A crystal field calculation shows that in CaF2's strong crystal field, the ground state of Ce2+ is a T2 level of the 4f5d configuration rather than the 4f configuration of the free ion. Measurements of the Zeeman effect confirm the T2 character of the ground state. The calculated energies and intensities of transitions from the ground state to 4f levels agree well with the observed optical absorption spectrum, especially in the near-infrared region.
This research news article discusses two studies that propose different models to explain an unusual gamma-ray burst (GRB) called the "Christmas burst" that occurred on Christmas Day in 2010.
One study suggests the GRB originated from a tightly bound binary system of a neutron star and supergiant helium star that merged, producing a jet within a common gas envelope. The other study proposes that a minor body like an asteroid or comet was tidally disrupted after passing close to a neutron star, producing debris that formed a disk and caused multiple emission peaks.
While both models can explain aspects of the complex data from the unusual GRB, the article notes that at least one model must be incorrect as the definitive proof
NVESTIGATING FEEDBACK AND RELAXATION IN CLUSTERS OF GALAXIES WITH THE CHANDRA...Kenneth Cavagnolo
Ā
Presented in this dissertation is an analysis of the X-ray emission from the intracluster medium (ICM) in clusters of galaxies observed with the Chandra X-ray Observatory. The cluster dynamic state is investigated via ICM temperature inhomogeneity, and ICM entropy is used to evaluate the thermodynamics of cluster cores.
This document presents the discovery of ring structures in the haloes of eight planetary nebulae, tripling the number known to have such rings. The rings are analyzed using image processing techniques to enhance their visibility. They find ring spacings range from less than 0.01 pc to 0.06 pc. This suggests ring spacing increases with time after the asymptotic giant branch phase. The properties of the rings support predictions of dust-driven wind instability models of mass loss but do not rule out other models. Analyzing the new detections provides insights into mass modulation processes late in stellar evolution.
1) The document investigates the nuclear activity of the barred spiral galaxy NGC 1672 using X-ray data from Chandra and XMM-Newton, as well as optical data from Hubble and infrared data from Spitzer.
2) It detects 28 X-ray sources within NGC 1672, with nine being ultraluminous X-ray sources located at the ends of the galaxy's bar.
3) For the first time, it shows NGC 1672 possesses a hard nuclear X-ray source surrounded by an X-ray bright circumnuclear star-forming ring, which dominates the central X-ray emission of the galaxy. The data indicates the nuclear source is a low-luminosity active gal
Assessment of Activity Concentration of The Naturally Occurring Radioactive M...IOSR Journals
Ā
The activity concentrations of potassium, Radium and thorium in soil samples from a mining site in yankandutse, Kaduna north western Nigeria were measured using gamma ray spectroscopy method. Activity concentration of potassium, Radium and thorium were determined. The activity concentrations of 40K, 226Ra and 232Th, respectively in Bq kg-1 in the soil samples ranged as follows: K-40 196.11Ā±2.02 to 553.03Ā±1.08 with average of 382.01, Ra-226 .1506Ā±.03 to 5.67Ā±.03 with average of 2.08 and Th-232 18.13Ā±3.19 to 73.09Ā±1.59 with average activity concentrations of 47.23 .The mean activity concentration of potassium and radium are below average but for thorium the activity concentration is above average.
This paper presents a study of the extended X-ray emission in the Seyfert galaxy NGC 4151 using deep Chandra observations. Key findings include:
1) Emission line maps show strong OVII, OVIII, and NeIX line emission extending along the northeast-southwest direction, consistent with an ionization cone.
2) Spectral analysis finds the extended emission is well described by photoionized plasma models, supporting a dominant role for nuclear photoionization.
3) Faint extended emission is also seen perpendicular to the ionization cone, indicating some leakage of nuclear ionizing radiation through warm absorbers rather than being blocked by an obscuring torus.
This document summarizes radio observations of the Type IIb supernova SN 2001ig made with the Australia Telescope Compact Array and Very Large Array over 700 days. The observations found periodic deviations from the standard model of radio light curves that are consistent with recurring density modulations in the circumstellar medium with a period of around 150 days. This provides evidence that the progenitor was a Wolf-Rayet star in a binary system with an eccentric 100 day orbit, causing regular build-up of circumstellar material. Such binary systems are thought to produce Type Ib/c supernovae through envelope stripping, linking these events to Type IIb supernovae.
The absorption spectrum of cerium-doped calcium fluoride (CaF2:Ce2+) was observed at several temperatures. At low temperatures, the spectrum consists of transitions from the ground state to levels of the 4f configuration. A crystal field calculation shows that in CaF2's strong crystal field, the ground state of Ce2+ is a T2 level of the 4f5d configuration rather than the 4f configuration of the free ion. Measurements of the Zeeman effect confirm the T2 character of the ground state. The calculated energies and intensities of transitions from the ground state to 4f levels agree well with the observed optical absorption spectrum, especially in the near-infrared region.
This research news article discusses two studies that propose different models to explain an unusual gamma-ray burst (GRB) called the "Christmas burst" that occurred on Christmas Day in 2010.
One study suggests the GRB originated from a tightly bound binary system of a neutron star and supergiant helium star that merged, producing a jet within a common gas envelope. The other study proposes that a minor body like an asteroid or comet was tidally disrupted after passing close to a neutron star, producing debris that formed a disk and caused multiple emission peaks.
While both models can explain aspects of the complex data from the unusual GRB, the article notes that at least one model must be incorrect as the definitive proof
NVESTIGATING FEEDBACK AND RELAXATION IN CLUSTERS OF GALAXIES WITH THE CHANDRA...Kenneth Cavagnolo
Ā
Presented in this dissertation is an analysis of the X-ray emission from the intracluster medium (ICM) in clusters of galaxies observed with the Chandra X-ray Observatory. The cluster dynamic state is investigated via ICM temperature inhomogeneity, and ICM entropy is used to evaluate the thermodynamics of cluster cores.
This document presents the discovery of ring structures in the haloes of eight planetary nebulae, tripling the number known to have such rings. The rings are analyzed using image processing techniques to enhance their visibility. They find ring spacings range from less than 0.01 pc to 0.06 pc. This suggests ring spacing increases with time after the asymptotic giant branch phase. The properties of the rings support predictions of dust-driven wind instability models of mass loss but do not rule out other models. Analyzing the new detections provides insights into mass modulation processes late in stellar evolution.
1) The document investigates the nuclear activity of the barred spiral galaxy NGC 1672 using X-ray data from Chandra and XMM-Newton, as well as optical data from Hubble and infrared data from Spitzer.
2) It detects 28 X-ray sources within NGC 1672, with nine being ultraluminous X-ray sources located at the ends of the galaxy's bar.
3) For the first time, it shows NGC 1672 possesses a hard nuclear X-ray source surrounded by an X-ray bright circumnuclear star-forming ring, which dominates the central X-ray emission of the galaxy. The data indicates the nuclear source is a low-luminosity active gal
Assessment of Activity Concentration of The Naturally Occurring Radioactive M...IOSR Journals
Ā
The activity concentrations of potassium, Radium and thorium in soil samples from a mining site in yankandutse, Kaduna north western Nigeria were measured using gamma ray spectroscopy method. Activity concentration of potassium, Radium and thorium were determined. The activity concentrations of 40K, 226Ra and 232Th, respectively in Bq kg-1 in the soil samples ranged as follows: K-40 196.11Ā±2.02 to 553.03Ā±1.08 with average of 382.01, Ra-226 .1506Ā±.03 to 5.67Ā±.03 with average of 2.08 and Th-232 18.13Ā±3.19 to 73.09Ā±1.59 with average activity concentrations of 47.23 .The mean activity concentration of potassium and radium are below average but for thorium the activity concentration is above average.
This paper presents a study of the extended X-ray emission in the Seyfert galaxy NGC 4151 using deep Chandra observations. Key findings include:
1) Emission line maps show strong OVII, OVIII, and NeIX line emission extending along the northeast-southwest direction, consistent with an ionization cone.
2) Spectral analysis finds the extended emission is well described by photoionized plasma models, supporting a dominant role for nuclear photoionization.
3) Faint extended emission is also seen perpendicular to the ionization cone, indicating some leakage of nuclear ionizing radiation through warm absorbers rather than being blocked by an obscuring torus.
This document summarizes a study analyzing far-infrared spectra of Saturn's rings obtained by the Cassini spacecraft. The authors modeled the spectra to estimate the size distribution of regolith grains on ring particles. They found that the spectra were best fit by a broad size distribution ranging from 1 micron to 1-10 cm, with a power law index of around 3. This suggests that the largest regolith grains are comparable in size to the smallest visible ring particles. The abundance of smaller grains was found to increase with decreasing solar phase angle, likely due to cooling effects in Saturn's shadow.
1) The Fermi bubbles are giant gamma-ray emitting structures extending above and below the galactic center.
2) The bubbles may have been formed by periodic capture of stars by the supermassive black hole at the galactic center, releasing energy of around 3x10^52 ergs per capture.
3) This energy injection could produce very hot plasma, accelerating electrons that produce radio and gamma-ray emission through synchrotron radiation and inverse Compton scattering.
Larsen L-ANS Winter Meeting San Diego CA - 0415-0417 - Nov 2012Lewis Larsen
Ā
This paper is part of the panel session "Discussion of
Low-Energy Nuclear Reactions." Enabled by many-body,
collective effects and appropriate forms of required input
energy (e.g., electric currents and/or organized magnetic
fields with tubular geometries can be used to produce
an electroweak reaction: e + p --> n + Ī½ ), LENRs involve elemental nucleosynthetic
transmutation reactions very much like stars, only at
vastly lower temperatures and pressures that are found in
laboratory apparatus such as electrolytic chemical cells
and many natural processes such as lightning discharges.
This document summarizes the discovery and analysis of a Type Ia supernova (SN Ia) at a redshift of 1.71, the most distant spectroscopically confirmed SN Ia at the time. The Hubble Space Telescope was used to obtain spectroscopy and photometry of the supernova. Analysis of the spectroscopy confirms it as a SN Ia with 92% confidence. The photometry is used to determine the supernova's distance, which agrees with the predictions of the ĪCDM cosmological model. This distant supernova helps improve constraints on the nature and behavior of dark energy in the early universe.
This study uses deep Chandra observations to examine the X-ray morphology of the circum-nuclear region of NGC 4151 on spatial scales down to 30 pc. Extended soft X-ray emission is detected out to 1.3 kpc from the nucleus, farther than seen in previous studies. The X-ray emission is more absorbed towards the boundaries of the ionization cone and perpendicular to the bicone, suggesting absorption by a torus. The innermost X-ray emission, coincident with H2 emission and dusty spirals, supports X-ray excitation of molecular gas. The extended X-ray emission may be due to hot gas heated by the AGN outflow or photoionized by past AGN activity.
The document summarizes a recent 150-ks Chandra observation of the galaxy merger NGC 6240. Extended soft X-ray emission is detected over a 110x80 kpc region around NGC 6240. Spectral analysis finds the emission comes from hot gas with a temperature of around 7.5 million K and a total mass of about 10^10 solar masses. The gas properties suggest widespread star formation over the past 200 Myr rather than a recent nuclear starburst. The fate of the diffuse hot gas after the galaxy merger is uncertain but it may be retained and evolve into the halo of an elliptical galaxy.
This document summarizes a study using deep Chandra observations of the Seyfert 1 galaxy NGC 4151. The observations allow examination of emission line morphology in the inner 150 pc region with high spatial resolution. The maps show structures correlated with the radio outflow and optical emission. There is evidence for jet-gas cloud interactions, including regions with elevated NeIX/OVII ratios and X-ray emission exceeding expectations from nuclear photoionization alone, suggesting collisional ionization. Constraints are also placed on the spatial distribution of iron KĪ± emission, finding less than 5% originates beyond 150 pc, in disagreement with a prior claim of 65% from larger regions.
The document summarizes observations of the luminous infrared galaxy NGC 2623 from multiple telescopes. Hubble Space Telescope images reveal over 100 bright star clusters in a 3.2 kpc extension south of the galaxy's nucleus, making it one of the richest concentrations of clusters observed. The clusters have ages between 1-100 Myr based on their optical colors. Archival GALEX data show the extension is very bright in far-ultraviolet but less significant at longer wavelengths. Spitzer data detect [Ne V] emission, confirming the presence of an active galactic nucleus. The off-nuclear star formation corresponds to a rate of 0.1-0.2 solar masses per year, while the bulk of the infrared
Hanle Effect Measurements of Spin Lifetime in Zn0.4Cd0.6Se Epilayers Grown on...Oleg Maksimov
Ā
This document summarizes a study that used the Hanle effect to measure spin lifetimes in ZnCdSe epilayers grown on InP substrates with varying n-doping levels. Four samples were studied: three Zn0.4Cd0.6Se samples with carrier densities of 8.0Ć1016 cm-3, 4.3Ć1017 cm-3, and 1.1Ć1018 cm-3, as well as an undoped Zn0.5Cd0.5Se sample. Measurements showed that spin lifetime varied non-monotonically with carrier density, reaching a maximum of ~10.5 ns for the sample near the metal-insulator transition.
This document summarizes the discovery of WISE J181417.29+341224.9 (WISE 1814+3412), the first hyper-luminous infrared galaxy (LIR > 1013 Lā) discovered by the Wide-field Infrared Survey Explorer (WISE). Follow-up images of WISE 1814+3412 revealed four nearby sources - a QSO, two Lyman Break Galaxies at z=2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission of WISE 1814+3412 and has a star formation rate of ~300Mā yrā1, accounting for <10% of the total luminosity. An obscured
This document summarizes a study of physical conditions in Barnard's Loop and the Orion-Eridanus Bubble, and implications for the Warm Ionized Medium component of the interstellar medium. The authors present new spectrophotometric observations of Barnard's Loop and use photoionization models to show that Barnard's Loop is photoionized by four candidate stars, but the models only agree with observations if Barnard's Loop has enhanced heavy element abundances by a factor of 1.4. Barnard's Loop resembles the brightest components of the Orion-Eridanus Bubble and Warm Ionized Medium. The models establish conditions that can explain the range of locations in diagnostic diagrams using a limited range of parameters
1996 strain in nanoscale germanium hut clusters on si(001) studied by x ray d...pmloscholte
Ā
This document summarizes a study that used x-ray diffraction and scanning tunneling microscopy to investigate the strain in nanoscale germanium hut clusters on silicon substrates. The key findings are:
1) X-ray diffraction measurements revealed contributions from the hut clusters that allowed determining the strain distribution uniquely from the clusters.
2) The germanium clusters are almost fully strained with 0.5% misfit at the interface but strain is relaxed towards the apex, with 4.2% misfit indicating the natural germanium lattice spacing.
3) By modeling the asymmetric intensity distributions around diffraction peaks, the study determined that strain is relaxed uniformly through the hut clusters from a maximum near the interface to a minimum
Investigation of a Partially Loaded Resonant Cavity_Zeller_KraftKurt Zeller
Ā
This experiment aimed to demonstrate the "EM Drive" effect using a tunable, partially loaded cylindrical cavity powered by a microwave oven magnetron. Testing revealed pendulum deflections caused by thermal effects from the magnetron leads, not anomalous thrust. Key factors like cavity quality factor and magnetron bandwidth must be considered to successfully analyze this anomaly. Although inconclusive, this highlighted design challenges that could help future experiments demonstrate the EM Drive effect if addressed.
MRS Spring 2009 Poster Rare Earth Diffused GaNmoluen
Ā
The document discusses research on rare earth (RE)-doped gallium nitride (GaN) films grown via diffusion doping with neodymium (Nd) and erbium (Er). Key findings include:
1) Nd-doped and Er-doped GaN samples exhibited room temperature ferromagnetism and near-infrared luminescence. Emission wavelengths matched telecommunications applications.
2) Increasing silicon doping decreased the ferromagnetic properties, as silicon competes with rare earths for gallium sites. Luminescence intensity was less affected by silicon doping.
3) Annealing time affected luminescence intensity, which increased then decreased with longer annealing, suggesting
This document discusses turbulence, mass loss, and HĪ± emission in the hypergiant star Ļ Cassiopeiae. It summarizes the star's extreme properties like high luminosity, irregular pulsations, and variable mass loss rate. It proposes that a stochastic field of shock waves can explain the observed mass loss rate, high microturbulent velocity, and HĪ± line profile. The document finds that adopting a Kolmogorov spectrum of shock waves characterized by a single parameter - the maximum Mach number - can successfully model these observed properties of the star.
1) The growth of the first stars was halted by ultraviolet radiation feedback from the stars themselves.
2) Radiation from the protostar evaporated the circumstellar accretion disk when the star's mass reached 43 times the mass of the Sun.
3) These massive primordial stars may help explain the lack of pair-instability supernovae signatures in ancient metal-poor stars.
The document analyzes morphological and compositional data of the central peak of Tycho crater on the Moon. Analysis of high-resolution Chandrayaan-1 and LRO data reveals evidence of volcanic features on the central peak, including volcanic vents, lava ponds showing cooling cracks, lava flows, and domes. Compositionally, M3 data show the central peak is heterogeneous and dominated by high-Ca pyroxene-rich rocks, with an anorthositic base. These morphological and mineralogical features suggest the central peak underwent multiple modifications after impact, exposing deep lunar crustal materials through volcanism triggered by the impact event.
This document appears to be a citation to a 1990 publication in the Publications of the Astronomical Society of the Pacific journal. However, without accessing the full text it is difficult to determine the key topics or essential information contained in the referenced publication based on the citation alone.
This document presents an analysis of metallicity gradients in the Milky Way disk as observed by the SEGUE survey. The key findings are:
1) The radial metallicity gradient (change in [Fe/H] with Galactic radius R) becomes flatter at heights above the plane (|Z|) greater than 1 kpc.
2) The median metallicity at large |Z| is consistent with outer disk open clusters, which also exhibit a flat radial gradient of [Fe/H] ā¼ -0.5.
3) A flat metallicity gradient at high |Z| has implications for models of thick disk formation, as different formation scenarios predict different metallicity patterns in the thick disk.
The document appears to be from the journal Science and contains data from the Curiosity rover measuring methane levels on Mars over multiple dates ("sols") since its landing in 2012. Tables show measurements of methane taken at night and day with information on atmospheric conditions. Average methane levels were calculated for groupings of sols labeled "low methane" and "high methane", with the high methane group showing levels over 7 parts per billion by volume.
The document summarizes observations of volcanic features associated with the lunar craters Tycho and Aristarchus. It finds that Tycho contains more viscous lava flows with higher albedos, indicating compositional differences from Aristarchus. "Lakes" on the crater rims are thought to consist of lava from vents. The crater floors likely contain lava that drained into subsurface chambers. Late eruptions at Aristarchus obscured floor details. Widespread deposits around the craters resulted from base surges, indicating large explosions formed the craters. Counts of impact craters on volcanic features date them at different times, with Aristarchus about 1.6 times older than Tycho, though the floors are roughly the same age.
The two largest impact basins recently discovered at Vesta's south pole are Rheasilvia and Veneneia. Rheasilvia is ~500 km wide and 19 km deep, making it one of the largest impact features on Vesta. It has a central massif and spiral ridge patterns on its floor. Veneneia is an older, partially buried ~400 km basin located beneath Rheasilvia. Crater counts date both basins to 1-2 billion years old, indicating major geological resetting of Vesta occurred relatively recently.
This document summarizes a study analyzing far-infrared spectra of Saturn's rings obtained by the Cassini spacecraft. The authors modeled the spectra to estimate the size distribution of regolith grains on ring particles. They found that the spectra were best fit by a broad size distribution ranging from 1 micron to 1-10 cm, with a power law index of around 3. This suggests that the largest regolith grains are comparable in size to the smallest visible ring particles. The abundance of smaller grains was found to increase with decreasing solar phase angle, likely due to cooling effects in Saturn's shadow.
1) The Fermi bubbles are giant gamma-ray emitting structures extending above and below the galactic center.
2) The bubbles may have been formed by periodic capture of stars by the supermassive black hole at the galactic center, releasing energy of around 3x10^52 ergs per capture.
3) This energy injection could produce very hot plasma, accelerating electrons that produce radio and gamma-ray emission through synchrotron radiation and inverse Compton scattering.
Larsen L-ANS Winter Meeting San Diego CA - 0415-0417 - Nov 2012Lewis Larsen
Ā
This paper is part of the panel session "Discussion of
Low-Energy Nuclear Reactions." Enabled by many-body,
collective effects and appropriate forms of required input
energy (e.g., electric currents and/or organized magnetic
fields with tubular geometries can be used to produce
an electroweak reaction: e + p --> n + Ī½ ), LENRs involve elemental nucleosynthetic
transmutation reactions very much like stars, only at
vastly lower temperatures and pressures that are found in
laboratory apparatus such as electrolytic chemical cells
and many natural processes such as lightning discharges.
This document summarizes the discovery and analysis of a Type Ia supernova (SN Ia) at a redshift of 1.71, the most distant spectroscopically confirmed SN Ia at the time. The Hubble Space Telescope was used to obtain spectroscopy and photometry of the supernova. Analysis of the spectroscopy confirms it as a SN Ia with 92% confidence. The photometry is used to determine the supernova's distance, which agrees with the predictions of the ĪCDM cosmological model. This distant supernova helps improve constraints on the nature and behavior of dark energy in the early universe.
This study uses deep Chandra observations to examine the X-ray morphology of the circum-nuclear region of NGC 4151 on spatial scales down to 30 pc. Extended soft X-ray emission is detected out to 1.3 kpc from the nucleus, farther than seen in previous studies. The X-ray emission is more absorbed towards the boundaries of the ionization cone and perpendicular to the bicone, suggesting absorption by a torus. The innermost X-ray emission, coincident with H2 emission and dusty spirals, supports X-ray excitation of molecular gas. The extended X-ray emission may be due to hot gas heated by the AGN outflow or photoionized by past AGN activity.
The document summarizes a recent 150-ks Chandra observation of the galaxy merger NGC 6240. Extended soft X-ray emission is detected over a 110x80 kpc region around NGC 6240. Spectral analysis finds the emission comes from hot gas with a temperature of around 7.5 million K and a total mass of about 10^10 solar masses. The gas properties suggest widespread star formation over the past 200 Myr rather than a recent nuclear starburst. The fate of the diffuse hot gas after the galaxy merger is uncertain but it may be retained and evolve into the halo of an elliptical galaxy.
This document summarizes a study using deep Chandra observations of the Seyfert 1 galaxy NGC 4151. The observations allow examination of emission line morphology in the inner 150 pc region with high spatial resolution. The maps show structures correlated with the radio outflow and optical emission. There is evidence for jet-gas cloud interactions, including regions with elevated NeIX/OVII ratios and X-ray emission exceeding expectations from nuclear photoionization alone, suggesting collisional ionization. Constraints are also placed on the spatial distribution of iron KĪ± emission, finding less than 5% originates beyond 150 pc, in disagreement with a prior claim of 65% from larger regions.
The document summarizes observations of the luminous infrared galaxy NGC 2623 from multiple telescopes. Hubble Space Telescope images reveal over 100 bright star clusters in a 3.2 kpc extension south of the galaxy's nucleus, making it one of the richest concentrations of clusters observed. The clusters have ages between 1-100 Myr based on their optical colors. Archival GALEX data show the extension is very bright in far-ultraviolet but less significant at longer wavelengths. Spitzer data detect [Ne V] emission, confirming the presence of an active galactic nucleus. The off-nuclear star formation corresponds to a rate of 0.1-0.2 solar masses per year, while the bulk of the infrared
Hanle Effect Measurements of Spin Lifetime in Zn0.4Cd0.6Se Epilayers Grown on...Oleg Maksimov
Ā
This document summarizes a study that used the Hanle effect to measure spin lifetimes in ZnCdSe epilayers grown on InP substrates with varying n-doping levels. Four samples were studied: three Zn0.4Cd0.6Se samples with carrier densities of 8.0Ć1016 cm-3, 4.3Ć1017 cm-3, and 1.1Ć1018 cm-3, as well as an undoped Zn0.5Cd0.5Se sample. Measurements showed that spin lifetime varied non-monotonically with carrier density, reaching a maximum of ~10.5 ns for the sample near the metal-insulator transition.
This document summarizes the discovery of WISE J181417.29+341224.9 (WISE 1814+3412), the first hyper-luminous infrared galaxy (LIR > 1013 Lā) discovered by the Wide-field Infrared Survey Explorer (WISE). Follow-up images of WISE 1814+3412 revealed four nearby sources - a QSO, two Lyman Break Galaxies at z=2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission of WISE 1814+3412 and has a star formation rate of ~300Mā yrā1, accounting for <10% of the total luminosity. An obscured
This document summarizes a study of physical conditions in Barnard's Loop and the Orion-Eridanus Bubble, and implications for the Warm Ionized Medium component of the interstellar medium. The authors present new spectrophotometric observations of Barnard's Loop and use photoionization models to show that Barnard's Loop is photoionized by four candidate stars, but the models only agree with observations if Barnard's Loop has enhanced heavy element abundances by a factor of 1.4. Barnard's Loop resembles the brightest components of the Orion-Eridanus Bubble and Warm Ionized Medium. The models establish conditions that can explain the range of locations in diagnostic diagrams using a limited range of parameters
1996 strain in nanoscale germanium hut clusters on si(001) studied by x ray d...pmloscholte
Ā
This document summarizes a study that used x-ray diffraction and scanning tunneling microscopy to investigate the strain in nanoscale germanium hut clusters on silicon substrates. The key findings are:
1) X-ray diffraction measurements revealed contributions from the hut clusters that allowed determining the strain distribution uniquely from the clusters.
2) The germanium clusters are almost fully strained with 0.5% misfit at the interface but strain is relaxed towards the apex, with 4.2% misfit indicating the natural germanium lattice spacing.
3) By modeling the asymmetric intensity distributions around diffraction peaks, the study determined that strain is relaxed uniformly through the hut clusters from a maximum near the interface to a minimum
Investigation of a Partially Loaded Resonant Cavity_Zeller_KraftKurt Zeller
Ā
This experiment aimed to demonstrate the "EM Drive" effect using a tunable, partially loaded cylindrical cavity powered by a microwave oven magnetron. Testing revealed pendulum deflections caused by thermal effects from the magnetron leads, not anomalous thrust. Key factors like cavity quality factor and magnetron bandwidth must be considered to successfully analyze this anomaly. Although inconclusive, this highlighted design challenges that could help future experiments demonstrate the EM Drive effect if addressed.
MRS Spring 2009 Poster Rare Earth Diffused GaNmoluen
Ā
The document discusses research on rare earth (RE)-doped gallium nitride (GaN) films grown via diffusion doping with neodymium (Nd) and erbium (Er). Key findings include:
1) Nd-doped and Er-doped GaN samples exhibited room temperature ferromagnetism and near-infrared luminescence. Emission wavelengths matched telecommunications applications.
2) Increasing silicon doping decreased the ferromagnetic properties, as silicon competes with rare earths for gallium sites. Luminescence intensity was less affected by silicon doping.
3) Annealing time affected luminescence intensity, which increased then decreased with longer annealing, suggesting
This document discusses turbulence, mass loss, and HĪ± emission in the hypergiant star Ļ Cassiopeiae. It summarizes the star's extreme properties like high luminosity, irregular pulsations, and variable mass loss rate. It proposes that a stochastic field of shock waves can explain the observed mass loss rate, high microturbulent velocity, and HĪ± line profile. The document finds that adopting a Kolmogorov spectrum of shock waves characterized by a single parameter - the maximum Mach number - can successfully model these observed properties of the star.
1) The growth of the first stars was halted by ultraviolet radiation feedback from the stars themselves.
2) Radiation from the protostar evaporated the circumstellar accretion disk when the star's mass reached 43 times the mass of the Sun.
3) These massive primordial stars may help explain the lack of pair-instability supernovae signatures in ancient metal-poor stars.
The document analyzes morphological and compositional data of the central peak of Tycho crater on the Moon. Analysis of high-resolution Chandrayaan-1 and LRO data reveals evidence of volcanic features on the central peak, including volcanic vents, lava ponds showing cooling cracks, lava flows, and domes. Compositionally, M3 data show the central peak is heterogeneous and dominated by high-Ca pyroxene-rich rocks, with an anorthositic base. These morphological and mineralogical features suggest the central peak underwent multiple modifications after impact, exposing deep lunar crustal materials through volcanism triggered by the impact event.
This document appears to be a citation to a 1990 publication in the Publications of the Astronomical Society of the Pacific journal. However, without accessing the full text it is difficult to determine the key topics or essential information contained in the referenced publication based on the citation alone.
This document presents an analysis of metallicity gradients in the Milky Way disk as observed by the SEGUE survey. The key findings are:
1) The radial metallicity gradient (change in [Fe/H] with Galactic radius R) becomes flatter at heights above the plane (|Z|) greater than 1 kpc.
2) The median metallicity at large |Z| is consistent with outer disk open clusters, which also exhibit a flat radial gradient of [Fe/H] ā¼ -0.5.
3) A flat metallicity gradient at high |Z| has implications for models of thick disk formation, as different formation scenarios predict different metallicity patterns in the thick disk.
The document appears to be from the journal Science and contains data from the Curiosity rover measuring methane levels on Mars over multiple dates ("sols") since its landing in 2012. Tables show measurements of methane taken at night and day with information on atmospheric conditions. Average methane levels were calculated for groupings of sols labeled "low methane" and "high methane", with the high methane group showing levels over 7 parts per billion by volume.
The document summarizes observations of volcanic features associated with the lunar craters Tycho and Aristarchus. It finds that Tycho contains more viscous lava flows with higher albedos, indicating compositional differences from Aristarchus. "Lakes" on the crater rims are thought to consist of lava from vents. The crater floors likely contain lava that drained into subsurface chambers. Late eruptions at Aristarchus obscured floor details. Widespread deposits around the craters resulted from base surges, indicating large explosions formed the craters. Counts of impact craters on volcanic features date them at different times, with Aristarchus about 1.6 times older than Tycho, though the floors are roughly the same age.
The two largest impact basins recently discovered at Vesta's south pole are Rheasilvia and Veneneia. Rheasilvia is ~500 km wide and 19 km deep, making it one of the largest impact features on Vesta. It has a central massif and spiral ridge patterns on its floor. Veneneia is an older, partially buried ~400 km basin located beneath Rheasilvia. Crater counts date both basins to 1-2 billion years old, indicating major geological resetting of Vesta occurred relatively recently.
This document reports on observations of comet 103P/Hartley 2 made by the WISE space telescope in May 2010 and additional ground-based telescopes. The WISE observations detected the comet's coma, nucleus, and dust trail. Analysis of the coma suggests dust particles larger than those observed for comet 81P/Wild 2. The extracted nucleus is estimated to be 0.6 km in radius. Emission detected at 4.6 microns may be from carbon monoxide or carbon dioxide gas. Carbon dioxide production rates are estimated to be 3.5Ć1024 molecules per second. The dust trail was detected with an optical depth of 9Ć10-10 and minimum mass of 4Ć1010 kg. These observations provide
The document summarizes the analysis of layered deposits inside the 174 km diameter Terby impact crater located on Mars. Stratigraphic and mineralogical analysis using multiple datasets suggests the deposits were formed subaqueously during the Noachian period. The thickest sequences display fan delta morphologies indicative of prograding/onlapping sedimentation over time. Phyllosilicates detected within layers support a sedimentary environment with sustained liquid water. Erosion during the Hesperian sculpted the current landforms, with later fluvial and then aeolian activity. Terby crater thus preserves a geologic record spanning multiple periods of Mars' history.
1. Chandra observations of the galaxy NGC 3351 revealed X-ray emission from its circumnuclear star-forming ring that is composed of numerous point-like sources embedded in diffuse hot gas.
2. The morphology of the X-ray emission is similar to but not identical with UV and H-alpha hot spots in the ring, which can be understood if star formation occurs through intermittent starbursts around the ring with different emissions tracing later evolutionary stages.
3. X-ray emission also extends beyond the ring, which is interpreted as outflowing gas from the ring into the disk and halo of NGC 3351, providing evidence for confined outflow near the plane but less restricted outflow perpendicular to
This document describes a study investigating the dynamical evolution of the Orion Nebula Cluster through N-body simulations. The simulations assume the cluster was initially much more compact than currently observed, based on evidence that a large fraction of gas was expelled during formation. This likely led to strong few-body relaxation effects early in the cluster's evolution. The simulations find that three-body interactions among massive stars could have ejected them from the cluster while also forming a very massive object through runaway stellar mergers. This object may have collapsed directly into a massive (~100 solar mass) black hole, which could explain the velocity dispersion of stars in the Trapezium system at the cluster core. The simulations further suggest this putative black hole has a ~70
This document reports the first detection of molecular gas (CO) in the shells of the galaxy Centaurus A (Cen A), located 15 kpc from the galaxy's center. The ratio of CO to HI emission in the shells matches what is found in the galaxy's central regions, which is unexpected given typical metallicity gradients in galaxies. The detection of molecular gas in the shells provides evidence that molecular gas in galaxy mergers may be spread further from nuclear regions than previously thought. The dynamics of the gas can be understood if the interstellar medium is considered clumpy and less dissipative than assumed, allowing dense gas to orbit with stars and form shells.
1) Barnard 68 is considered a stable dense molecular cloud core, but observations indicate it should be gravitationally unstable and collapsing.
2) The authors argue Barnard 68 is experiencing a collision with another small core that will trigger its gravitational collapse within the next 200,000 years, forming a low-mass star.
3) Such core mergers may play an important role in triggering star formation and shaping properties of molecular cores and the stellar initial mass function.
Cosmological simulations of structure formation predict that galaxy clusters continue to grow and evolve through ongoing
mergers with group-scale systems. During these merging events, the ram pressure applied by the intracluster medium acts to strip
the gas from the infalling groups, forming large tails of stripped gas, which eventually become part of the main cluster. In this
work, we present a detailed analysis of our new deep Chandra observations of the NGC 4839 group falling into the nearby Coma
cluster, providing a unique opportunity to explore the way galaxy clusters in the local universe continue to grow. Our analysis
reveals a cold front feature at the leading head of the group, preceded by a bow shock of hot gas in front with a Mach number
of ā¼ 1.5. The power spectrum of surface brightness fluctuations in the tail shows that the slope gets less steep as the distance
from the leading head increases, changing from ā2.35+0.07
ā0.06 at the inner part of the tail to ā1.37+0.09
ā0.07 at the outermost part of
the tail. These values are shallower than the slope of the Kolmogorov 2D power spectrum, indicating that thermal conduction is
being suppressed throughout the tail, enabling long-lived small-scale turbulence, which would typically be washed out if thermal
conduction was not inhibited. The characteristic amplitude of surface brightness fluctuations in the tail suggests a mild level of
turbulence with a Mach number in the range of 0.1ā0.5, agreeing with that found for the infalling group in Abell 2142.
This document summarizes a study of X-ray emission from circumstellar material (CSM) in the remnant of Kepler's supernova. The researchers used a statistical technique to isolate X-ray emission from CSM versus ejecta based on spectral characteristics. They found that most CSM is distributed along the bright north rim, but substantial amounts are also projected against the center, indicating a disk-like distribution of CSM from the progenitor system before the supernova. Hydrodynamic simulations support an AGB star companion as the origin of the asymmetric CSM. Quantitative analysis of magnesium emission identifies CSM and requires Kepler to have originated from a close binary system.
This document describes the discovery of three new globular clusters in the Local Group dwarf irregular galaxy NGC 6822. The authors present optical photometry of the clusters from archival CFHT/Megacam data. Two clusters are luminous and compact, while the third is a lower luminosity diffuse cluster. The positions of the new clusters are consistent with the linear alignment of previously known clusters in NGC 6822. Studying globular cluster systems in dwarf galaxies provides insights into the formation of larger galaxies through accretion and mergers.
ALMA observations of the Seyfert 2 galaxy NGC 1433 reveal a nuclear gaseous spiral structure within a nuclear ring encircling a nuclear stellar bar. Near the nucleus, there is intense high-velocity CO emission interpreted as an AGN-driven molecular outflow. The outflow involves a molecular mass of 3.6 million solar masses and a flow rate of about 7 solar masses per year. Continuum emission at the center is likely thermal dust emission from a molecular torus expected in this Seyfert 2 galaxy. The observations probe gas dynamics within 24 parsecs of the active galactic nucleus.
1) A gas cloud is approaching the Milky Way's central black hole and is expected to make its closest approach in mid-2013.
2) Observations of this close approach may provide new insights into the environment surrounding the black hole.
3) The gas cloud is very small, about the size of our solar system, and will be disrupted by tidal forces as it nears the black hole, potentially causing increased brightness of the black hole.
This document summarizes the analysis of Kepler photometry data for the exoplanet Kepler-7b. Key findings include:
1) The occultation depth is measured to be 44Ā±5 ppm, translating to a Kepler geometric albedo of 0.32Ā±0.03, the most precise value measured for an exoplanet.
2) The planetary orbital phase lightcurve is characterized with an amplitude of 42Ā±4 ppm.
3) Atmospheric modeling finds it unlikely that the high albedo is due to a dominant thermal component. Two possible explanations are proposed: excess reflection from clouds/hazes, or depleted atmospheric sodium and potassium allowing Rayleigh scattering to dominate.
The ALMA observations of NGC 1433 reveal a nuclear gaseous spiral structure within the central kpc. This spiral winds up into a pseudo-ring at ~200 pc from the center. Near the nucleus, there is intense high-velocity CO emission up to 200 km/s that is interpreted as an outflow, involving 3.6 million solar masses of molecular gas and a flow rate of ~7 solar masses per year. The outflow could be driven by both the central star formation and AGN through its radio jets. Continuum emission at 0.87 mm is detected only at the very center and likely comes from thermal dust emission from the molecular torus expected in this Seyfert 2 galaxy.
The document summarizes a study of an extreme molecular cloud in the Antennae galaxies that has properties consistent with forming a globular cluster. ALMA observations reveal a cloud with a radius of 24 pc and mass greater than 5 million solar masses. While capable of forming a globular cluster, a lack of associated thermal radio emission indicates star formation has not yet begun to alter the environment, suggesting the cloud is in an early stage of evolution. For the cloud to be confined as observed, an external pressure over 10,000 times greater than typical interstellar pressure is required, supporting the theory that high pressures are needed to form globular clusters in extreme environments like mergers.
Using observations from the Very Large Telescope, astronomers have discovered a dense gas cloud approximately three times the mass of Earth that is falling towards the supermassive black hole at the center of the Milky Way. The cloud is on a highly eccentric orbit that will bring it as close as 3,100 times the event horizon of the black hole in 2013. Over the past three years, the cloud has begun to disrupt due to tidal shearing from the black hole's gravitational forces, and its dynamic evolution over the next few years will provide insights into the black hole's accretion processes.
The XMM-Newton satellite observed the young open star cluster NGC 6231 for a total of 180 kiloseconds, providing an unprecedented X-ray view. Around 600 point-like X-ray sources were detected, including many early-type O stars. The data helped refine the relationship between X-ray and bolometric luminosities for O stars, finding less scatter than previously thought, with the main exception being X-ray emission from wind interactions in binary systems. The data also provided insight into the low-mass pre-main sequence star population and star formation history of the cluster.
This document summarizes a study on the formation of polar ring galaxies through two proposed scenarios: the merging scenario and the accretion scenario. The merging scenario involves a head-on collision between two galaxies, where one becomes the host galaxy and the other's gas forms the polar ring. The accretion scenario involves tidal interactions that allow gas from one galaxy to be accreted by another galaxy to form a polar ring. Through simulations, the study finds that both scenarios can produce stable polar rings, but that the accretion scenario better matches observed properties of polar ring galaxies, such as the frequency and morphology of the rings. The study concludes the accretion scenario is both more likely and more supported by observations to explain how most polar ring galaxies form.
- The document discusses three massive (107 Mā) star clusters located near the inner Lindblad resonance (ILR) ring in the barred spiral galaxy NGC 1365.
- The clusters, designated M4, M5, and M6, are embedded in dense molecular gas and dust in the bar dust lane where it enters the ILR ring.
- The gas flows into the bar from the spiral region, accumulating at a rate of ~40 Mā/yr near the ILR, fueling ongoing star formation in the nucleus.
- The document analyzes the gas flows and physical conditions to infer that the clusters likely formed where an interbar gas filament impacts the bar dust lane, triggering
This document presents aluminum abundances for about 100 red giant stars in each of the Galactic globular clusters 47 Tuc and M 4. The abundances were derived from intermediate-resolution FLAMES/GIRAFFE spectra, focusing on the Al I doublet at 8772-8773 Ć . Previous homogeneous abundances of O, Na, Mg, and Si were also analyzed to study multiple stellar populations in these clusters. The data confirm two stellar populations are visible in M 4, while 47 Tuc shows evidence of at least three distinct stellar groups based on the abundances of O, Na, Mg, Al, and N.
This document summarizes a study using Hubble Space Telescope images to further examine the dark core detected in the galaxy cluster A520 in a previous study using ground-based data. The HST data provides over 3 times as many galaxies that can be used for weak lensing analysis, significantly enhancing the mass reconstruction. The analysis confirms the detection of the dark core coincident with the X-ray peak but lacking luminous galaxies at over 10 sigma significance. Several substructures are also clearly detected, including a new one labeled P5. However, the comparison of dark matter, hot gas, and galaxy distributions remains peculiar compared to other merging clusters.
This document summarizes a study of the galaxy NGC 3801 using panchromatic data from radio, ultraviolet, optical and infrared wavelengths. The study finds that NGC 3801 is a post-merger early-type galaxy that shows evidence of recent star formation in spiral wisps as well as feedback from active galactic nucleus jets. Specifically, the galaxy has a young radio jet that has not yet impacted the outer gaseous regions, but will likely quench star formation within the next 10 million years and further transform the galaxy into a red elliptical. The multi-wavelength data reveal complex gas and dust structures that may be due to a kinematically decoupled core or warped disk.
Magmatic iron-meteorite parent bodies are the earliest planetesimals in the Solar System,and they preserve information about conditions and planet-forming processes in thesolar nebula. In this study, we include comprehensive elemental compositions andfractional-crystallization modeling for iron meteorites from the cores of five differenti-ated asteroids from the inner Solar System. Together with previous results of metalliccores from the outer Solar System, we conclude that asteroidal cores from the outerSolar System have smaller sizes, elevated siderophile-element abundances, and simplercrystallization processes than those from the inner Solar System. These differences arerelated to the formation locations of the parent asteroids because the solar protoplane-tary disk varied in redox conditions, elemental distributions, and dynamics at differentheliocentric distances. Using highly siderophile-element data from iron meteorites, wereconstruct the distribution of calcium-aluminum-rich inclusions (CAIs) across theprotoplanetary disk within the first million years of Solar-System history. CAIs, the firstsolids to condense in the Solar System, formed close to the Sun. They were, however,concentrated within the outer disk and depleted within the inner disk. Future modelsof the structure and evolution of the protoplanetary disk should account for this dis-tribution pattern of CAIs.
The shorelines of Titanās hydrocarbon seas trace flooded erosional landforms such as river valleys; however, it isunclear whether coastal erosion has subsequently altered these shorelines. Spacecraft observations and theo-retical models suggest that wind may cause waves to form on Titanās seas, potentially driving coastal erosion,but the observational evidence of waves is indirect, and the processes affecting shoreline evolution on Titanremain unknown. No widely accepted framework exists for using shoreline morphology to quantitatively dis-cern coastal erosion mechanisms, even on Earth, where the dominant mechanisms are known. We combinelandscape evolution models with measurements of shoreline shape on Earth to characterize how differentcoastal erosion mechanisms affect shoreline morphology. Applying this framework to Titan, we find that theshorelines of Titanās seas are most consistent with flooded landscapes that subsequently have been eroded bywaves, rather than a uniform erosional process or no coastal erosion, particularly if wave growth saturates atfetch lengths of tens of kilometers.
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ā¼ 106Mā black hole (BH) that is currently in the process of āturning onā. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1āW2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ā¼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ā¼ 106Mā AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: activeā accretion, accretion discsā galaxies: individual: SDSS J133519.91+072807.4
We present the JWST discovery of SNā2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
ā
27.82088
with a host spectroscopic redshift of
2.903
Ā±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SNāIa, SNā2023adsy is both fairly red (
ļæ½
ā¢
(
ļæ½
ā
ļæ½
)
ā¼
0.9
) despite a host galaxy with low-extinction and has a high CaāII velocity (
19
,
000
Ā±
2
,
000
km/s) compared to the general population of SNeāIa. While these characteristics are consistent with some Ca-rich SNeāIa, particularly SNā2016hnk, SNā2023adsy is intrinsically brighter than the low-
ļæ½
Ca-rich population. Although such an object is too red for any low-
ļæ½
cosmological sample, we apply a fiducial standardization approach to SNā2023adsy and find that the SNā2023adsy luminosity distance measurement is in excellent agreement (
ā²
1
ā¢
ļæ½
) with
Ī
CDM. Therefore unlike low-
ļæ½
Ca-rich SNeāIa, SNā2023adsy is standardizable and gives no indication that SNāIa standardized luminosities change significantly with redshift. A larger sample of distant SNeāIa is required to determine if SNāIa population characteristics at high-
ļæ½
truly diverge from their low-
ļæ½
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the RāI spectral index by 1.0 Ā±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted BrĪ³ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual HāK and KāL colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (ā15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 Ā± 20ā¦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holesā stars: formationā Galaxy: centerā galaxies: star formation
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 Mā) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10ā4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ādarkā gravitational force describing the āelasticā response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newtonās constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ādark gravity forceā explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Context. With a mass exceeding several 104 Mā and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 Ć 10ā8 photons cmā2
s
ā1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The Milky Wayās (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
ālast major merger.ā Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8ā11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1ā2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1ā2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ālast major mergerā
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Ioās surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Ioās trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Ioās surface using adaptive
optics at visible wavelengths.
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4ā0.9Āµm) and novel JWST images with 14 filters spanning 0.8ā5Āµm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3Āµm to construct an ultradeep image, reaching as deep as ā 31.4 AB mag in the stack and
30.3-31.0 AB mag (5Ļ, r = 0.1ā circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 ā 15. These objects show compact half-light radii of R1/2 ā¼ 50 ā 200pc, stellar masses of
Mā ā¼ 107ā108Mā, and star-formation rates of SFR ā¼ 0.1ā1 Mā yrā1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ā¼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol Ā» - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 Ā± 0.05 Rā,a3Ļ mass upper limit of
3.9 Mā, and an equilibrium temperature of 315 Ā± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 Ā± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 Ā± 0.00006 d and a radius of 1.0 Ā± 0.1 Rā, resulting in an equilibrium temperature of ā¼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003ā0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moonāforming giant impact(MGI). Earlier studies found an increase in Earth's coreāmantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large lowāshear velocity provinces (LLSVPs). Here,we show that a hot postāimpact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ā¼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heatāproducing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earthās next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (FāØ;
approximately +2.5% W mā2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammalsā continued survival,
predicted background pCO2 levels of 410ā816 ppm combined with increased
FāØ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and FāØ
play a critical role in planetary habitability.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Ā
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Ā
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
Ā
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Ā
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Ā
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Donāt worry, we can help with all of this!
Weāll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. Weāll provide examples and solutions for those as well. And naturally weāll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
āHow Axelera AI Uses Digital Compute-in-memory to Deliver Fast and Energy-eff...Edge AI and Vision Alliance
Ā
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/how-axelera-ai-uses-digital-compute-in-memory-to-deliver-fast-and-energy-efficient-computer-vision-a-presentation-from-axelera-ai/
Bram Verhoef, Head of Machine Learning at Axelera AI, presents the āHow Axelera AI Uses Digital Compute-in-memory to Deliver Fast and Energy-efficient Computer Visionā tutorial at the May 2024 Embedded Vision Summit.
As artificial intelligence inference transitions from cloud environments to edge locations, computer vision applications achieve heightened responsiveness, reliability and privacy. This migration, however, introduces the challenge of operating within the stringent confines of resource constraints typical at the edge, including small form factors, low energy budgets and diminished memory and computational capacities. Axelera AI addresses these challenges through an innovative approach of performing digital computations within memory itself. This technique facilitates the realization of high-performance, energy-efficient and cost-effective computer vision capabilities at the thin and thick edge, extending the frontier of what is achievable with current technologies.
In this presentation, Verhoef unveils his companyās pioneering chip technology and demonstrates its capacity to deliver exceptional frames-per-second performance across a range of standard computer vision networks typical of applications in security, surveillance and the industrial sector. This shows that advanced computer vision can be accessible and efficient, even at the very edge of our technological ecosystem.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Ā
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind fĆ¼r viele in der HCL-Community seit letztem Jahr ein heiĆes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und LizenzgebĆ¼hren zu kƤmpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer mƶglich. Das verstehen wir und wir mƶchten Ihnen dabei helfen!
Wir erklƤren Ihnen, wie Sie hƤufige Konfigurationsprobleme lƶsen kƶnnen, die dazu fĆ¼hren kƶnnen, dass mehr Benutzer gezƤhlt werden als nƶtig, und wie Sie Ć¼berflĆ¼ssige oder ungenutzte Konten identifizieren und entfernen kƶnnen, um Geld zu sparen. Es gibt auch einige AnsƤtze, die zu unnƶtigen Ausgaben fĆ¼hren kƶnnen, z. B. wenn ein Personendokument anstelle eines Mail-Ins fĆ¼r geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche FƤlle und deren Lƶsungen. Und natĆ¼rlich erklƤren wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt nƤherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Ćberblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und Ć¼berflĆ¼ssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps fĆ¼r hƤufige Problembereiche, wie z. B. Team-PostfƤcher, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
What is an RPA CoE? Session 1 ā CoE VisionDianaGray10
Ā
In the first session, we will review the organization's vision and how this has an impact on the COE Structure.
Topics covered:
ā¢ The role of a steering committee
ā¢ How do the organizationās priorities determine CoE Structure?
Speaker:
Chris Bolin, Senior Intelligent Automation Architect Anika Systems
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
Ā
Inconsistent user experience and siloed data, high costs, and changing customer expectations ā Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
Ever-changing customer expectations demand more modern digital experiences, and the bank needed to find a solution that could provide real-time data to its customer channels with low latency and operating costs. Join this session to learn how Citizens is leveraging Precisely to replicate mainframe data to its customer channels and deliver on their āmodern digital bankā experiences.
Dandelion Hashtable: beyond billion requests per second on a commodity serverAntonios Katsarakis
Ā
This slide deck presents DLHT, a concurrent in-memory hashtable. Despite efforts to optimize hashtables, that go as far as sacrificing core functionality, state-of-the-art designs still incur multiple memory accesses per request and block request processing in three cases. First, most hashtables block while waiting for data to be retrieved from memory. Second, open-addressing designs, which represent the current state-of-the-art, either cannot free index slots on deletes or must block all requests to do so. Third, index resizes block every request until all objects are copied to the new index. Defying folklore wisdom, DLHT forgoes open-addressing and adopts a fully-featured and memory-aware closed-addressing design based on bounded cache-line-chaining. This design offers lock-free index operations and deletes that free slots instantly, (2) completes most requests with a single memory access, (3) utilizes software prefetching to hide memory latencies, and (4) employs a novel non-blocking and parallel resizing. In a commodity server and a memory-resident workload, DLHT surpasses 1.6B requests per second and provides 3.5x (12x) the throughput of the state-of-the-art closed-addressing (open-addressing) resizable hashtable on Gets (Deletes).
Monitoring and Managing Anomaly Detection on OpenShift.pdfTosin Akinosho
Ā
Monitoring and Managing Anomaly Detection on OpenShift
Overview
Dive into the world of anomaly detection on edge devices with our comprehensive hands-on tutorial. This SlideShare presentation will guide you through the entire process, from data collection and model training to edge deployment and real-time monitoring. Perfect for those looking to implement robust anomaly detection systems on resource-constrained IoT/edge devices.
Key Topics Covered
1. Introduction to Anomaly Detection
- Understand the fundamentals of anomaly detection and its importance in identifying unusual behavior or failures in systems.
2. Understanding Edge (IoT)
- Learn about edge computing and IoT, and how they enable real-time data processing and decision-making at the source.
3. What is ArgoCD?
- Discover ArgoCD, a declarative, GitOps continuous delivery tool for Kubernetes, and its role in deploying applications on edge devices.
4. Deployment Using ArgoCD for Edge Devices
- Step-by-step guide on deploying anomaly detection models on edge devices using ArgoCD.
5. Introduction to Apache Kafka and S3
- Explore Apache Kafka for real-time data streaming and Amazon S3 for scalable storage solutions.
6. Viewing Kafka Messages in the Data Lake
- Learn how to view and analyze Kafka messages stored in a data lake for better insights.
7. What is Prometheus?
- Get to know Prometheus, an open-source monitoring and alerting toolkit, and its application in monitoring edge devices.
8. Monitoring Application Metrics with Prometheus
- Detailed instructions on setting up Prometheus to monitor the performance and health of your anomaly detection system.
9. What is Camel K?
- Introduction to Camel K, a lightweight integration framework built on Apache Camel, designed for Kubernetes.
10. Configuring Camel K Integrations for Data Pipelines
- Learn how to configure Camel K for seamless data pipeline integrations in your anomaly detection workflow.
11. What is a Jupyter Notebook?
- Overview of Jupyter Notebooks, an open-source web application for creating and sharing documents with live code, equations, visualizations, and narrative text.
12. Jupyter Notebooks with Code Examples
- Hands-on examples and code snippets in Jupyter Notebooks to help you implement and test anomaly detection models.
The Microsoft 365 Migration Tutorial For Beginner.pptxoperationspcvita
Ā
This presentation will help you understand the power of Microsoft 365. However, we have mentioned every productivity app included in Office 365. Additionally, we have suggested the migration situation related to Office 365 and how we can help you.
You can also read: https://www.systoolsgroup.com/updates/office-365-tenant-to-tenant-migration-step-by-step-complete-guide/
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Ā
Are you ready to revolutionize how you handle data? Join us for a webinar where weāll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, weāll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sourcesāfrom PDF floorplans to web pagesāusing FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether itās populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
Weāll wrap up with a live Q&A session where you can engage with our experts on your specific use cases, and learn more about optimizing your data workflows with AI.
This webinar is ideal for professionals seeking to harness the power of AI within their data management systems while ensuring high levels of customization and security. Whether you're a novice or an expert, gain actionable insights and strategies to elevate your data processes. Join us to see how FME and AI can revolutionize how you work with data!
Driving Business Innovation: Latest Generative AI Advancements & Success Story
Ā
Abell 2052
1. Accepted for publication in ApJ
Preprint typeset using L TEX style emulateapj v. 03/07/07
A
A VERY DEEP CHANDRA OBSERVATION OF ABELL 2052: BUBBLES, SHOCKS, AND SLOSHING
E. L. Blanton1,2 , S. W. Randall2 , T. E. Clarke3 C. L. Sarazin4 , B. R. McNamara5,2,6 , E. M. Douglass1 , and M.
McDonald7
Accepted for publication in ApJ
ABSTRACT
We present ļ¬rst results from a very deep (ā¼ 650 ksec) Chandra X-ray observation of Abell 2052, as
arXiv:1105.4572v2 [astro-ph.CO] 16 Jun 2011
well as archival VLA radio observations. The data reveal detailed structure in the inner parts of the
cluster, including bubbles evacuated by the AGNās radio lobes, compressed bubble rims, ļ¬laments,
and loops. Two concentric shocks are seen, and a temperature rise is measured for the innermost one.
On larger scales, we report the ļ¬rst detection of an excess surface brightness spiral feature. The spiral
has cooler temperatures, lower entropies, and higher abundances than its surroundings, and is likely
the result of sloshing gas initiated by a previous cluster-cluster or sub-cluster merger. Initial evidence
for previously unseen bubbles at larger radii related to earlier outbursts from the AGN is presented.
Subject headings: galaxies: clusters: general ā cooling ļ¬ows ā intergalactic medium ā radio contin-
uum: galaxies ā X-rays: galaxies: clusters ā galaxies: clusters: individual(A2052)
1. INTRODUCTION quantities of cool gas (as evidenced by star formation
With its sub-arcsec resolution, the Chandra X-ray Ob- rates, for example) were not found to match the gas cool-
servatory has revealed a wealth of substructure in the ing rates estimated from earlier X-ray observatories. The
X-ray-emitting intracluster medium (ICM) in clusters of X-ray cooling rates have lowered based on Chandra and
galaxies. āCavitiesā or ābubblesā are commonly seen in XMM-Newton observations, and the majority of the gas
the X-ray gas in cluster centers related to outbursts by is seen to cool to only some fraction (typically one-third
the active galactic nucleus (AGN). In addition, surface to one-half) of the cluster average temperature (Peterson
brightness edges associated with shocks and cold fronts et al. 2003). A heating mechanism is required to stop the
have been observed, as well as spiral features likely re- gas from cooling to even lower temperatures.
lated to āsloshingā of the intracluster medium in cluster The most likely candidate for heating of the central
centers. cluster gas is feedback from central AGN that are fed
The central bubbles are frequently seen in cooling ļ¬ow by the cooling gas (see McNamara & Nulsen 2007 for a
(or ācool coreā) clusters and are often ļ¬lled with radio review). This heating comes in the form of bubbles in-
emission associated with the AGN. There was some ev- ļ¬ated by the AGN, described above, that then rise buoy-
idence for these features in a very few cases even be- antly to larger radii in cluster atmospheres distributing
fore Chandra observations (e.g. ROSAT observations of the heat. The details of this heating, however, are still
Perseus [BĀØhringer et al. 1993], Abell 4059 [Huang &
o not completely understood. In addition, there is at least
Sarazin 1998], and Abell 2052 [Rizza et al. 2000]). Clus- some component of shock heating in many cluster cen-
ters with cool cores have radio bubbles much more of- ters, especially early on in the AGNās lifetime. Shocks
ten than non-cool core clusters (e.g. Mittal et al. 2009), have been detected in fewer cases than radio bubbles,
and some of the most spectacular individual cases ob- and observations include those of Perseus (Fabian et al.
served by Chandra are the Perseus cluster (Fabian et 2003, 2006; Graham et al. 2008), M87/Virgo (Forman
al. 2003, 2006), M87/Virgo (Forman et al. 2005, 2007), et al. 2005), Hydra A (Nulsen et al. 2005a), Hercules A
Hydra A (McNamara et al. 2000, Wise et al. 2007), (Nulsen et al. 2005b), MS0735.6+7421 (McNamara et al.
MS0735.6+7421 (McNamara et al. 2005), and Abell 2052 2005), and the group NGC 5813 (Randall et al. 2011).
(Blanton et al. 2001, 2003, 2009, 2010). Typically, the shocks are weak with Mach numbers rang-
The classic ācooling ļ¬ow problemā is that suļ¬cient ing from approximately 1.2 to 1.7 (McNamara & Nulsen
2007). In even fewer cases are temperature rises detected
1 Institute for Astrophysical Research and Astronomy Depart- associated with the shocks.
ment, Boston University, 725 Commonwealth Avenue, Boston, MA Heating of the ICM may also result from gas āslosh-
02215; eblanton@bu.edu, emdoug@bu.edu ingā in the clusterās central potential well (Ascasibar &
2 Harvard Smithsonian Center for Astrophysics, 60 Garden
Street, Cambridge, MA 02138; srandall@head.cfa.harvard.edu; Markevitch 2006; ZuHone et al. 2010). Cold fronts, re-
ELB as Visiting Scientist gions where the surface brightness changes sharply but
3 Naval Research Laboratory, 4555 Overlook Avenue SW, Wash-
the pressure does not, can result from these sloshing mo-
ington D. C. 20375; tracy.clarke@nrl.navy.mil tions driven initially by cluster or sub-cluster mergers.
4 Department of Astronomy, University of Virginia, P. O. Box
400325, Charlottesville, VA 22904-4325; sarazin@virginia.edu The sloshing can produce a spiral distribution of cool
5 Department of Physics and Astronomy, University of Waterloo, cluster gas reaching into the cluster center (e.g. Clarke
Waterloo, ON N2L 2G1, Canada; mcnamara@sciborg.uwaterloo.ca
6 Perimeter Institute for Theoretical Physics, 31 Caroline St., N.
et al. 2004, LaganĀ“ et al. 2010), and is also seen in galaxy
a
groups (Randall et al. 2009a).
Waterloo, Ontario, Canada, N2L 2Y5
7 Astronomy Department, University of Maryland, College Park, Here, we present a very deep Chandra observation of
MD 20742; mcdonald@astro.umd.edu the cool core cluster Abell 2052. The only other cool core
2. 2 Blanton et al.
clusters observed to similar or greater depth with Chan- frequencies were imaged with a 4.3ā²ā² circular beam. We
dra are Perseus (Fabian et al. 2006) and M87/Virgo (Mil- have blanked all pixels in the spectral index map that
lion et al. 2010, Werner et al. 2010). Abell 2052 is a mod- were lower than the 5Ļ level on either of the input maps.
erately rich cluster at a redshift of z = 0.03549 (Oegerle
& Hill 2001). Its central radio source, 3C 317, is hosted 4. IMAGES
by the central cD galaxy, UGC 09799. Abell 2052 was Merged X-ray images of the source were created. The
previously observed in the X-ray with Einstein (White, images were corrected using merged background images
Jones, & Forman 1997), ROSAT (Peres et al. 1998, Rizza and exposure maps. An image showing the combined
et al. 2000), ASCA (White 2000), Chandra (Blanton et data from all CCD chips used in the analysis (ACIS S1,
al. 2001, 2003, 2009, 2010), Suzaku (Tamura et al. 2008), S2, S3, I2, and I3) in the 0.3 ā 10.0 keV band is shown in
and XMM-Newton (de Plaa et al. 2010). In addition, we Fig. 1. This ļ¬gure illustrates the diļ¬erent roll angles that
present archival radio observations from the Very Large were used when the observations were performed. The
Array (VLA). extended cluster emission is visible, as well as numerous
We assume Hā¦ = 70 km sā1 Mpcā1 , ā¦M = 0.3, and point sources which appear more extended while increas-
ā¦Ī = 0.7 (1ā²ā² = 0.7059 kpc at z = 0.03549) throughout. ingly oļ¬-axis due to the larger PSF in these regions. The
Errors are given at the 1Ļ level unless otherwise stated. image has been smoothed with a 3ā²ā² Gaussian.
An unsmoothed image in the 0.3 ā 2.0 keV band of the
2. CHANDRA OBSERVATIONS AND DATA REDUCTION central region of the cluster is shown in Fig. 2. The image
Abell 2052 was observed with Chandra for a total of reveals exquisite detail related to the interaction of the
662 ksec in Cycles 1, 6, and 10 from 2000 ā 2009. A sum- AGN with the ICM. Point sources, including the central
mary of the observations is given in Table 1. All obser- AGN, are visible. Cavities or bubbles to the N and S of
vations were performed with the ACIS-S as the primary the AGN are seen, as well as outer cavities to the NW
instrument. The ACIS-S was chosen for its greater re- and SE. The inner cavities are bounded by bright, dense,
sponse at low energies than the ACIS-I, yielding a higher rims, and the NW cavity is surrounded by a very narrow,
count rate for this relatively cool, kT ā 3 keV cluster. ļ¬lamentary loop. A ļ¬lament extends into the N bubble.
The nominal roll angles used for the observations varied A shock is seen exterior to the bubbles and rims, and a
from 99ā¦ to 265ā¦ providing coverage at large radii at a probable second shock is visible to the NE.
range of azimuthal angles around the cluster. The events ā² ā²
A three-color image of the central 6. 56 Ć 6. 56 region of
were telemetered in Very Faint mode for all but the Cy- A2052 is displayed in Fig. 3. The image has been slightly
cle 1 observation, where the events were telemetered in ā²ā²
smoothed, using a 1. 5 Gaussian, and the scaling for each
Faint mode. The data were processed in the standard of the three colors is logarithmic. Red represents the soft
manner, using CIAO 4.2 and CALDB 4.2.2. After clean- (0.3 ā 1.0 keV) band, green is medium (1.0 ā 3.0 keV),
ing, and ļ¬ltering for background ļ¬ares (using the 2.5 ā and blue represents the hard band (3.0 ā 10.0 keV). The
7.0 keV range for the BI chips and the 0.3 ā 12.0 keV bright rims surrounding the inner bubbles appear cool.
range for the FI chips), the total exposure remaining for The ļ¬rst shock exterior to the bubble rims is slightly
the eleven data sets was 657 ksec. Background correc- elliptical with the major axis in the north-south direction
tions were made using the blank-sky background ļ¬elds, (Blanton et al. 2009). It is visible as a discontinuity in
including the new āperiod Eā background ļ¬les for the the surface brightness, and the bluish color is consistent
more recent data. For each target events ļ¬le, a corre- with a temperature rise in this region. Outside of the
sponding background events ļ¬le was created, normaliz- inner shock, a second surface brightness discontinuity is
ing by the ratio of counts in the 10 ā 12 keV energy range seen as greenish emission in this ļ¬gure. The discontinuity
for the source and background ļ¬les to set the scaling. is sharper to the NE and more extended to the SW. This
feature may represent a shock or a cold front. These
3. RADIO DATA features will be explored in further detail in Ā§6.
We have used the NRAO data achive to extract ob- A composite X-ray/optical/radio image is shown in
servations of 3C 317 at 4.8 and 1.4 GHz. A summary Fig. 4. The 0.3 ā 2.0 keV Chandra image is shown in red,
of the data sets is presented in Table 2. The archival radio emission at 4.8 GHz from the VLA is displayed as
radio data were calibrated and reduced with the NRAO blue, and optical r-band emission from the Sloan Digi-
Astronomical Image Processing System (AIPS). Images tal Sky Survey (SDSS; Abazajian et al. 2009) is shown
were produced through the standard Fourier transform as green. The AGN is visible in the X-ray, radio, and
deconvolution method for each frequency and conļ¬gura- optical, and the radio lobes ļ¬ll the cavities in the X-ray
tion. Several loops of imaging and self-calibration were emission. This includes the inner cavities as well as an
undertaken for each data set to reduce the eļ¬ects of phase outer cavity bounded by a narrow loop to the NW and
and amplitude errors in the data. The ļ¬nal radio image the outer cavity to the S/SE. In addition, the radio emis-
at 4.8 GHz was obtained through combining the three sion is breaking through the northern bubble rim to the
VLA conļ¬gurations and two observing frequencies. We north. The X-ray ļ¬lament extending from the northern
have also produced a combined conļ¬guration image at bubble rim towards the AGN was found to be associated
1.4 GHz but do not show it as the structure is remark- with HĪ± emission in Blanton et al. (2001). In Fig. 5,
ably similar to the 4.8 GHz image. we show SDSS r-band contours superposed on a Chan-
We have made a spectral index map between 1.4 GHz dra image in the 0.3 ā 10.0 keV range that has been
ā²ā²
and 4.8 GHz to compare the spectral features more di- smoothed with a 1. 5 radius Gaussian. The central cD
rectly with the X-ray structure. This map was created galaxy is oriented in the NE-SW direction in the optical.
from the combined conļ¬guration data at each frequency. The inner bubbles seen in the X-ray emission are within
The uv-coverage of both data sets was matched and both the cD galaxy.
3. Very Deep Chandra Observation of A2052 3
4.1. Residual Images the 0.3ā2.0 keV image, the center of the large scale emis-
ā²ā²
In order to better reveal features in the X-ray image, sion was found to be only 1. 2 away from the position of
we created residual images using two diļ¬erent techniques. the AGN. The emission was found to be slightly ellip-
In the ļ¬rst, we used the method of unsharp-masking, and tical, with an ellipticity value of 0.18 Ā± 0.00081 (where
in the second, we subtracted a 2D beta model from the ellipticity values range from 0 to 1, with 0 indicating cir-
X-ray image. We ļ¬nd that unsharp-masking is useful cular emission). The position angle for the semi-major
for highlighting the structure in the inner parts of the axis of the ellipse is 38.2 Ā± 0.1ā¦ measured north towards
cluster, while the model subtraction is better at revealing east. The core radius using this model is 25.1 Ā± 0.060ā²ā²
larger-scale features. and the beta index is Ī² = 0.46 Ā± 0.00021.
The residual image after 2D beta model subtraction in
4.1.1. Unsharp-masking the 0.3 ā 2.0 keV band in shown in Fig. 7. The image
ā²ā²
has been smoothed with a 7. 38 radius Gaussian. The
We created an unsharp-masked image in the 0.3 ā 10.0 smoothing washes out the details in the very center of the
keV energy range. Sources were detected in the image image, but the bright bubble rims are clearly visible. A
using the wavelet detection tool āwavdetectā in CIAO spiral feature is seen, starting in the SW and extending to
(Freeman et al. 2002). Several wavelet scales were used, the NE. Similar spiral structures have been seen in other
ā²ā²
at 1, 2, 4, 8, and 16 pixels, where 1 pixel = 0. 492. clusters, with A2029 being a particularly clear example
Sources detected using this method were visually exam- (Clarke et al. 2004).
ined and several were rejected as being clumpy X-ray gas
emission rather than point sources. A source-free image 5. X-RAY SPECTRAL MAPS
was created by replacing the source pixel values with Spectral maps were created to examine the distribu-
the average value found in an annulus surrounding each tion of temperature, as well as entropy, pressure, and
source. We retained the sources in our unsharp-masked abundance using the technique described in Randall et
image while making corrections with a source-free image. al. (2008, 2009b). The temperature maps were created by
Smoothed images, both with and without sources, were extracting spectra for the separate Chandra observations
ā²ā²
created by smoothing with a 0. 98 radius Gaussian. An- and ļ¬tting them simultaneously in the 0.6ā7.0 keV range
other copy of the source-free image was smoothed with with a single temperature APEC model, with NH set to
ā²ā²
a 9. 8 Gaussian. A summed image was made by combin- the Galactic value of 2.71 Ć 1020 cmā2 (Dickey & Lock-
ing the source-free images smoothed at the two diļ¬erent man 1990) and the abundance allowed to vary. Back-
scales. A diļ¬erence image was made by subtracting the ground spectra were extracted from the blank sky back-
ā²ā² ā²ā²
9. 8 Gaussian-smoothed source-free image from the 0. 98 ground observations that were reprojected to match each
Gaussian-smoothed image that contained sources. Fi- data set. Data from both the frontside- and backside-
nally, the unsharp-masked image was created by divid- illuminated (FI and BI) chips were used, with separate
ing the diļ¬erence image by the summed image. In this response ļ¬les and normalizations determined for each
way, we retain the sources in the image, smoothed at a ObsIDās data set, with the FI and BI normalizations
ā²ā²
scale of 0. 98. This method is similar to that in Fabian allowed to vary independently for each ObsID. Spectra
et al. (2006), although sources are excluded throughout were extracted with a minimum of either 2000 or 10000
in their unsharp-masked images. background-subtracted counts, corresponding to a mini-
The unsharp-masked image is displayed in Figure 6 mum SNR of approximately 45 or 100, respectively, de-
with VLA 4.8 GHz radio contours superposed. The bub- pending on our analysis goals. The radius of the circu-
bles in the X-ray emission are more easily seen in this lar extraction region was allowed to grow to the size re-
image, as are the bright bubble rims, the shock exterior quired to extract the minimum counts. Spectral maps of
to the bubble rims, and the second shock or cold front the central region of A2052 were previously presented in
feature to the NE. The radio emission ļ¬lls the inner bub- Blanton et al. (2003, 2009). Here, with the much deeper
bles and the southern lobe turns to ļ¬ll the outer southern Chandra data, we are able to examine a much larger re-
bubble. The radio lobe to the north appears to be es- gion of the cluster with high precision. We have chosen to
caping through a gap in the northern bubble rim, and a include spectral maps created as described above rather
narrow ļ¬lament is seen in the radio in this region. The than Voronoi-Tesselation maps, even though some of the
radio emission also extends beyond the bubble rims to map pixels are not independent (some regions used in
the NW to ļ¬ll a small bubble bounded by a narrow X- spectral ļ¬tting overlap), especially in the outer regions
ray ļ¬lament. To the east, an extension in the radio ļ¬lls of the maps. We ļ¬nd that spectral structures are easier
a small depression in the X-ray on the scale of approxi- to see on the maps we present, and they are conļ¬rmed
mately 10ā²ā² . by extracting spectral proļ¬les in Ā§6 and Ā§7.
ā²ā²
In Fig. 8, we display a high-resolution (0. 492 pixels)
4.1.2. Beta-model subtraction
temperature map of the central region of A2052, where
A 2D beta model was used to ļ¬t the surface brightness the minimum number of net counts was 2000. Super-
in both 0.3 ā 2.0 keV and 0.3 ā 10.0 keV images using a posed on the temperature map are X-ray surface bright-
ā² ā²ā²
circular region with radius 5. 66. The images were source- ness contours derived from the 1. 5 Gaussian-smoothed
free, with the surface brightness at the position of sources 0.3 ā 10.0 keV image. The coolest parts of the cluster are
approximated from the surface brightness in an annulus found in the brightest parts of the X-ray rims surround-
around each source, as above. Corrections were made for ing the bubbles, including the bright rim to the W and
exposure, using a merged exposure map. Similar results NW, the E-W bar that passes through the cluster center
were obtained for the ļ¬ts to the images in both energy and AGN, and the N ļ¬lament that extends into the N
bands. Errors were computed using Cash statistics. For bubble. An overlay of HĪ± contours from McDonald et
4. 4 Blanton et al.
al. (2010) onto the high-resolution temperature map is along the direction of the spiral toward the cluster center,
shown in Fig. 9. For comparison, the HĪ± contours are beyond the extent of the inner spiral contours.
ā²ā²
superposed onto the 0.3 ā 10.0 keV, 1. 5 radius Gaussian A higher-resolution temperature map showing the
smoothed, Chandra image in Fig. 10. The correspon- same f.o.v. as in Fig. 12 is displayed in Fig. 13. The spec-
dence between the HĪ± emission and both the surface tra were extracted with a minimum of 2000 background-
brightness and temperature structure is excellent. HĪ± subtracted counts, and the pixel size is 4ā²ā² . The map
emission, representing gas with T ā 104 K, is detected represents more than 80000 spectral ļ¬ts. Here, the er-
in the brightest and coolest structures in the cluster cen- rors range from 2% in the inner regions to approximately
ter, including the E-W bar and the ļ¬lament that extends 14% in the outskirts. Two views of a pseudo-pressure
into the N bubble. While correspondence between HĪ± map derived from the ļ¬ts that were used to make the
and X-ray surface brightness was shown in Blanton et al. temperature map in Fig. 13 are shown is Figs. 14 and 15.
(2001), with the deeper Chandra and new HĪ± data pre- The pressure jump corresponding to the innermost shock
sented here, we see more detail in the association, includ- is clearly seen, as well as evidence for pressure structure
ing the ļ¬lament extending into the N bubble not reaching tracing the second inner shock (seen in the outer X-ray
the AGN (whereas it appeared to reach the AGN in HĪ± contour). There is no evidence of structure in the pres-
in the Baum et al. (1988) data shown in Blanton et sure map related to the spiral structure.
al. (2001)). The association between the HĪ± and X-ray A pseudo-entropy map is displayed in Fig. 16 with ex-
indicates that at least some gas is cooling from the tem- cess surface brightness contours after subtracting a beta
perature associated with the X-ray gas in these regions model superposed. The map was derived using the spec-
(T ā 107 K) to T ā 104 K. McDonald et al. (2010) and tral ļ¬ts that resulted in the temperature map in Fig.
McDonald et al. (2011) suggested that this gas represents 13. We deļ¬ne pseudo-entropy as kT (A)ā1/3 , with A de-
gas that was previously cooler and then ionized to pro- ļ¬ned as above. In general, the entropy decreases toward
duce the HĪ± emission. Given the low UV-to-HĪ± ratio the cluster center. There appears to be correspondence
in this system, they conclude that the ionization source between structure in the entropy map and the spiral fea-
would likely be shocks related to the AGN rather than ture.
nearby, luminous, stars, as in some other cluster centers. A projected abundance map is shown in Fig. 17, cor-
Additionally, signiļ¬cant clumpy substructure in the responding to the temperature map in Fig. 12 with 8ā²ā²
temperature distribution is seen in the gas throughout pixels and a minimum of 10000 background-subtracted
the central cluster region. This substructure will be fur- counts per pixel. Errors range from 5% in the highest
ther investigated in an upcoming paper. Errors range surface brightness regions, to 23% in the outer regions of
from approximately 2% in the very central, brightest re- the map (with the majority of the errors at the 10 ā 15%
gions, to approximately 12% in the outer areas of the level across the map). To the SW, a region of high abun-
map. dance is coincident with the high surface-brightness spi-
In Fig. 11, we show a projected or āpseudoā pressure ral. This is consistent with higher metallicity gas sloshing
map of the central region of A2052. The map was de- away from the cluster center, creating the spiral. A high-
rived using the APEC normalization and temperature metallicity region was found at a similar position to the
from the spectral ļ¬ts that resulted in the temperature SW using XMM-Newton data (de Plaa et a. 2010).
map in Fig. 8. The APEC normalization is proportional
6. INNER SHOCK FEATURES
to n2 V , where n is density and V is the volume projected
along the line of sight. We deļ¬ne the projected pressure In Blanton et al. (2009), we identiļ¬ed two inner sur-
as kT (A)1/2 , where A is the APEC normalization scaled face brightness jumps that were likely associated with
by area to account for extraction regions that may go oļ¬ shocks. These jumps are visible in Figs. 3, 6, and 15.
the edge of the chips. Superposed on the pressure map The ļ¬rst inner jump extends around the cluster center
are X-ray surface brightness contours in the 0.3 ā 10.0 in a slightly elliptical shape in the N-S direction at a
keV band. The most obvious feature in the map is the radius of approximately 40ā²ā² . The second jump is ellip-
clear ring of high pressure that is coincident with the in- tical in the NE to SW direction, and is sharper and at
ner discontinuity seen in surface brightness and the jump a smaller radius from the AGN in the NE direction. To
in density (Blanton et al. 2009) visible in Figs. 2 and 3. the NE, the second jump is at a radius of approximately
The bubbles, including the inner bubbles to the N and S 65ā²ā² .
of the AGN as well as the outer, small NW bubble and Similar to Blanton et al. (2009), we have ļ¬tted a pro-
the outer SE bubble, are visible as lower-pressure regions jected spherical density model to the surface brightness
in this projected pressure map since they are largely de- in a NE wedge with PA ā2ā¦ to 98ā¦ measured east from
void of X-ray-emitting gas. north. The projected model characterizes the density us-
A lower-resolution temperature map covering a larger ing power laws and discontinuous jumps. We use three
region of the center is shown in Fig. 12. Here, the mini- power laws, and identify two density jumps. See Randall
mum number of background-subtracted counts is 10000, et al. (2008) for further description of this technique.
and the pixel size is 8ā²ā² . The errors in temperature range Our results are generally consistent with, and a reļ¬ne-
from 1% in the inner regions to 5% in the outskirts of ment of, those presented in Blanton et al. (2009). The
the frame. Superposed are the residual surface bright- density jumps are at radii of 44.2 Ā± 0.1 arcsec (31.2 Ā± 0.1
ness contours in the 0.3 ā 2.0 keV band after beta-model kpc) and 66.3+0.3 arcsec (46.8+0.02 kpc), respectively,
ā0.06 ā0.04
subtraction (see Fig. 7). The spiral excess traces out a from the AGN. The magnitudes of the jumps are fac-
+0.016 +0.010
region of temperature lower than its surroundings. In tors of 1.25ā0.015 and 1.29ā0.012 , for the ļ¬rst and second
addition, this low temperature feature continues inward jumps, respectively. The slopes of the three power-law
components, going from the inner to outer regions, are
5. Very Deep Chandra Observation of A2052 5
ā0.53+0.029 , ā1.25+0.030 , and ā1.06+0.0067 .
ā0.024 ā0.037 ā0.0084 inward from the annulus just inside the shock bound-
The jumps in density correspond to Mach numbers of ary. This may indicate that the temperature of the gas
1.17+0.011 and 1.20+0.0072 , respectively, for the ļ¬rst and
ā0.010 ā0.0079 just inside the shock boundary was also previously much
second jumps. The temperature is then expected to rise lower before being shocked, and then the rise in tempera-
a similar amount inside both shocks (a factor of 1.16 for ture in this region may be higher than we have estimated
the ļ¬rst shock and 1.19 for the second shock). above.
We have calculated a deprojected temperature proļ¬le In addition, we ļ¬tted a projected density model to the
for the NE region, shown in Fig. 18. Dashed lines indi- surface brightness proļ¬le in a wedge to the SW with PA
cate the locations of the two shocks. As with all of our 250ā¦ to 340ā¦ from N out to a radius of 100ā²ā² to charac-
spectral ļ¬ts, spectra were extracted separately for each terize the inner shocks in this direction. We ļ¬nd similar
data set and ļ¬tted simultaneously in XSPEC v12.6. The results to the SW as we did to the NE for the ļ¬rst inner
ļ¬ts were performed in the 0.6 ā 7.0 keV range. A sin- shock. We ļ¬nd a density jump of a factor of 1.26 Ā± 0.025
gle APEC model plus Galactic absorption was ļ¬tted to at a radius of 48 Ā± 0.4 arcsec (34 Ā± 0.3 kpc). However, as
the outermost annulus spectra with abundance allowed can be seen in the surface brightness distribution in the
to vary. The contribution of emission from this shell to images (i.e. Fig. 3), the second inner shock edge seems
the next annulus in was calculated using geometric pro- less sharp and extends to larger radii in the SW than in
jection, assuming spherically symmetric shells, and the the NE. We do not ļ¬nd a density jump corresponding to
APEC normalization scaled appropriately to account for the second inner shock to the SW, only a change in slope
the projection of this outer component. The parameters at a radius of 107 arcsec (75.5 kpc).
for the contribution from the outer annulus were frozen,
and an additional APEC model was added for the an- 7. SPIRAL FEATURE
nulus of interest. This procedure was continued inward, The spiral feature visible in Fig. 7 is similar to that
where the spectral model for each annulus included con- seen in simulations of gas sloshing in cluster centers (As-
tributions from all external annuli. See Blanton et al. casibar & Markevitch 2006). The sloshing sets up cold
(2003) for further description. fronts and the distinctive spiral morphology. We there-
In addition, in Fig. 18, we present density and pres- fore would expect the excesses seen in Fig. 7 to be visible
sure proļ¬les for the NE region. The density and pres- as excesses in surface brightness proļ¬les containing these
sure were determined from the deprojected spectral ļ¬ts, regions. Temperature proļ¬les should show cooler gas co-
since the normalization of the free APEC component for incident with the surface brightness enhancements. In
each annulus is proportional to the square of density at addition, the simulations predict that the bright, slosh-
that annulus. Note that the radius range extends to ap- ing, spiral region will contain gas of lower entropy as
proximately 300ā²ā² (212 kpc) where the overdensity (the cluster central gas is displaced to larger radii. As shown
density relative to the critical density) is ā 12500. For in Ā§5, the spiral excess is coincident with regions of low
comparison, an overdensity of 500 (r500 ) is at r ā 800 temperature and entropy in projected maps.
kpc (ā 1100ā²ā²). We have extracted surface brightness proļ¬les from
A clear rise in temperature is seen inside the innermost wedges in three directions: SW, NE, and NW. The SW
shock, in addition to the jumps in density and pressure corresponds to the bright, inner part of the spiral, while
in this region. In Blanton et al. (2009), while the tem- the NE includes the outer region of the spiral, and the
peratures inside and outside this shock were consistent NW is largely free from any spiral excess emission and
with the rise expected given the Mach number, the best- serves as a comparison region. The sectors used for the
ļ¬tting temperatures were approximately ļ¬at across the proļ¬les are shown superposed on the 0.3 ā 2.0 keV resid-
shock. Here, with the much deeper data set, the rise is ual image in Fig. 19. The surface brightness proļ¬les for
clearly detected. Just outside the shock, the temperature the three regions are shown in Fig. 20. Error bars are
is kT = 2.81+0.11 keV, while inside the shock it reaches
ā0.15 smaller than the symbols. Relative to the NW, non-
kT = 3.14+0.11 keV, a factor of 1.12+0.10 higher, with a
ā0.11 ā0.08
spiral region, the SW shows excess emission from ap-
signiļ¬cance or 2.1Ļ. Such temperature rises associated proximately 60ā²ā² ā 195ā²ā² (42 ā 138 kpc), corresponding to
with weak shocks are extremely diļ¬cult to measure in the inner part of the sprial. To the NE, excess emission
cluster centers, with very deep, high resolution observa- is seen beyond approximately 110ā²ā² (78 kpc). Note that
tions required. the enhancement in the NW in the ā 10 ā 20ā²ā² (7 ā 14
For the second shock, the situation is less obvious. The kpc) region shows that the bubble rims are brightest in
best-ļ¬tting temperatures are appproximately ļ¬at across this region, which also corresponds to cooler gas seen in
the shock: kT = 3.35+0.20 keV outside the shock and
ā0.16
HĪ± (Figs. 9, 10).
kT = 3.27+0.14 keV inside the shock. Therefore, even We have extracted spectra in the three wedges and
ā0.15
within the errors, this is inconsistent with the expected determined projected temperature proļ¬les. The spectra
temperature jump of 1.19, with the highest rise permit- were extracted separately for each of the observations
ted giving a factor of 1.07. However, as noted above, as well as for the corresponding background ļ¬les. The
temperature rises associated with weak shocks are very spectra for each region were ļ¬tted simultaneously using
diļ¬cult to detect, and due to projection eļ¬ects, mea- an APEC thermal plasma model. Absorption was ļ¬xed
sured rises are expected to be lower than might be ex- at the Galactic value and elemental abundances were al-
pected based on shock strengths alone (e.g. Randall et al. lowed to vary. Projected temperature proļ¬les comparing
2011). In addition, the gas may cool due to adiabatic ex- the SW and NW (non-spiral) regions and the NE and
pansion (McNamara & Nulsen 2007). Also, we note that NW regions are shown in Figs. 21 and 22, respectively.
the temperature drops precipitously in the next annulus In both cases, signiļ¬cant drops in temperature are seen
in the regions corresponding to the surface-brightness ex-
6. 6 Blanton et al.
cesses associated with the spiral described above. In seen to the E. These features are all ļ¬lled with 4.8 GHz
addition, the high surface brightness ā 10ā²ā² ā 20ā²ā² (7 ā radio emission as seen in Fig. 6. As described in Ā§3,
14 kpc) region in the NW has cooler temperatures than we created a radio spectral index map using the 1.4 and
those radii regions to the SW and NE. This is likely due, 4.8 GHz VLA data. The map is shown in Fig. 26 with
ā²ā²
at least in part, to the larger contribution to the emis- contours of 1. 5 Gaussian-smoothed X-ray emission in the
sion measure from the bright, compressed, cool, bubble 0.3 ā 10.0 keV band superposed.
rims to the NW at these radii as compared to the same The spectral index is ļ¬attest at the position of the
radii to the SW and NE, where the bubble rims are not radio and X-ray core, and steepens into the radio lobes.
as bright. The regions we have identiļ¬ed as outer bubbles, to the
In order to examine the bright region of the spiral to NW and SE, are associated with regions with distinctly
the SW in more detail, we have ļ¬tted a projected den- steeper spectral indices. This is consistent with these
sity model to the surface brightness proļ¬le, as described bubbles resulting from an earlier stage in the current
above for the NE sector shock ļ¬ts. To focus on the cold outburst, or from a separate, earlier AGN outburst, since
front / spiral edge, we ļ¬t only regions with r > 70ā²ā² . We the high-energy electrons age faster than the lower energy
ļ¬nd a density jump of a factor of 1.12+0.022 at a radius
ā0.011
electrons, resulting in steepening of the spectrum over
of 154 Ā± 1.5 arcsec (109 Ā± 1 kpc) from the cluster center. time. The radio emission āleakingā out of the N bubble
We extracted spectra in larger bins to the SW, and through the bubble rim directly N of the AGN has a
performed a spectral deprojection as described above for spectral index consistent with that ļ¬lling the N lobe,
the NE. Proļ¬les of temperature, density, and pressure making it likely that this emission is part of the current
are shown in Fig. 23. Dashed lines, going from smaller AGN outburst.
to larger annuli, indicate the positions of the ļ¬rst inner Obvious additional bubbles are not seen outside of
shock, the second inner shock / edge, and the exterior this central region in the images, including the unsharp-
edge of the cold front / SW spiral. Since the deprojec- masked images. Also, lower frequency radio emission at
tion introduces some scatter, particularly in the region 330 MHz (Zhao et al. 1993) has a similar extent as the
between the inner shocks, we have also plotted the pro- 1.4 and 4.8 GHz emission. To search for more bubbles
jected temperature proļ¬le as well as the pressure proļ¬le at larger radii, we have made a pressure-diļ¬erence map.
using the projected temperatures (shown as open cir- The map was created by ļ¬tting a 2D beta model to a
cles). A temperature rise is seen associated with the ļ¬rst pressure map with 8ā²ā² bins, and a minimum of 10000
inner shock, but not the second inner shock. A clear background-subtracted counts for each region used for a
density fall oļ¬ is seen at the outer edge of the SW spi- spectral ļ¬t. This corresponds to the temperature map
ral. The temperatures within the sprial region are cooler shown in Fig. 12. The center was ļ¬xed to the position
than those outside of it. found in the 2D beta model ļ¬t to the surface brightness,
Projected abundance proļ¬les to the SW and NE are described in 4.1.2. The values for the ellipticity and po-
shown in Fig. 24. The dashed line marks the outer edge sition angle of the ellipse, 0.17 and 119ā¦ from W, respec-
of the spiral to the SW (at r = 154ā²ā² , as determined tively, were similar to those found for the surface bright-
above). The abundance is higher in the bright, SW, spi- ness ļ¬t. The pressure-diļ¬erence map is shown in Fig. 27,
ral region, than in the corresponding radial region to the with 4.8 GHz radio contours superposed. Regions of low
NE. Proļ¬les of entropy for the SW and NE regions are pressure are evident to the N and S of the AGN, along
2/3 the current axis of the radio source. For both the N and
shown in Fig. 25. The entropy is deļ¬ned as S = kT /ne ,
S apparently low-pressure regions on the map, we have
and projected temperature values were used. As in Fig.
extracted spectra within circular apertures covering the
24, the outer edge of the SW spiral region is marked
regions, as well as comparison regions in surrounding cir-
with a dashed line. There is clearly a cross-over in the
cular annuli. We have calculated āprojectedā pressures,
entropy proļ¬les for the SW and NE regions near this ra-
dius. From r ā 70 ā 150ā²ā² , low entropy values are found deļ¬ned as kT (A)1/2 , where A is the APEC normaliza-
coincident with the SW spiral excess. In the NE, the spi- tion, for the apparent bubbles (low pressure regions) and
ral excess is at larger radii, and this is seen in the entropy the comparison annuli. For the N bubble, we ļ¬nd a sig-
proļ¬le, where the values are low in the NE with radii niļ¬cance in the lower projected pressure of 2.3Ļ com-
greater than approximately 190ā²ā² . This is striking con- pared to the comparison annulus, and for the S bubble,
ļ¬rmation of the predictions from sloshing models, where the signiļ¬cance is 2.2Ļ. These regions of lower pressure
central, low entropy, cluster gas is displaced to larger may represent outer bubbles from an earlier outburst (or
radii (i.e. Ascasibar & Markevitch 2006). multiple earlier outbursts) of the AGN. Future higher dy-
The sum of the evidence, including the surface bright- namic range radio data may give further evidence that
ness proļ¬les, and temperature, abundance, and entropy these features are related to AGN activity.
distributions, points to the spiral being a cold front / Approximating both of these possible bubbles as
sloshing feature resulting from an oļ¬-axis merger earlier spheres with radii of 34 kpc, located 75 kpc from the clus-
in the clusterās history. ter center, we calculate their energy input into the ICM
as E = 4P V (Churazov et al. 2002). This assumes that
the bubbles are ļ¬lled with relativistic plasma (Ī³ = 4/3).
8. X-RAY CAVITIES Using the average pressure at the cluster radius of 75 kpc
Clear cavities (or ābubblesā) in the X-ray emission are of P ā 6 Ć 10ā11 dyn cmā2 , we ļ¬nd that each bubble
seen in the Chandra images to the N and S of the AGN. can add 1 Ć 1060 erg to the ICM.
In addition, there is a small bubble bounded by a narrow
X-ray ļ¬lament to the NW and a bubble separated from
the S bubble to the SE. A very small depression is also 9. DISCUSSION AND CONCLUSIONS
7. Very Deep Chandra Observation of A2052 7
We have presented ļ¬rst results from a very deep Chan- than its surroundings in both temperature maps and sec-
dra observation of Abell 2052. Detailed structure is seen tor proļ¬les. Regions of low entropy are found coincident
in the inner part of the cluster, including bubbles, bright with the spiral surface-brightness excess. Finally, the
shells, and ļ¬laments. Radio emission at 4.8 GHz is seen abundance is higher in the spiral region than its sur-
to ļ¬ll bubbles to the N and S of the AGN, as well as roundings. This is consistent with central, low-entropy,
outer bubbles to the NW and SE, and a small bubble to high-metallicity gas sloshing out to larger radii. There-
the E. HĪ± emission is coincident with the brightest and fore, sloshing can play a part in redistributing the met-
coolest regions in the cluster center, including the E-W als within a cluster (Simionescu et al. 2010, de Plaa et
bar and the ļ¬lament in the N bubble, indicating that at al. 2010). Outbursts from the AGN also play a role in
least some gas is cooling to T ā 104 K. metal redistribution (Kirkpatrick et al. 2009). Detailed
An inner shock is clearly seen surrounding the cluster measurements of the spectral properties of similar diļ¬use
center, as well as a second feature exterior to the ļ¬rst spiral excesses have only rarely been measured. While
that is also most likely a shock. Both edges in surface LaganĀ“ et al. (2010), for example, presented evidence
a
brightness can be described as arising from shocks with of excess surface-brightness spirals in several systems, in
Mach numbers ā 1.2. For the inner shock, evidence for many cases temperature declines were not detected as-
an associated temperature rise is seen in a three-color sociated with the spiral features, and if they were, they
image. Also, a temperature proļ¬le reveals a signiļ¬cant were most often only measured for the bright, inner spiral
increase inside this region, consistent with that expected regions.
given the shock strength. Such temperature rises associ- While the radio emission shows clear correspondence
ated with weak shocks driven by AGN in the centers of with deļ¬cits in the X-ray emission, and the extended ra-
cool core clusters have only rarely been measured, given dio structure is likely related to typical radio lobes from
the narrow widths of the shocks, the small magnitudes the AGN, there may be some component of radio mini-
of the temperature rises, and the cooling related to adia- halo emission. A correlation has been found between
batic expansion and the projection of cluster gas at larger the presence of sloshing features in clusters and mini-
radii. halos (ZuHone, Markevitch, & Brunetti 2011), and these
A spiral feature is seen, and is well-described as re- mini-halos may result from reacceleration of relativistic
sulting from gas sloshing related to a cluster-cluster or electrons by turbulence associated with sloshing (Maz-
sub-cluster merger earlier in the lifetime of A2052. There zotta & Giacintucci 2008). With our current radio data,
is also evidence of dynamical activity in the cluster from however, we do not see obvious correspondence between
optical spectroscopy: the central cD has a fairly large pe- the radio emission and the spiral sloshing feature.
culiar velocity (290 Ā± 90 km sā1 ) relative to the cluster There is evidence for outer bubbles related to one or
mean (Oergerle & Hill 2001). The X-ray spiral is bright- more earlier outbursts from the AGN. While not seen
est to the SW, and continues around the cluster center in the surface brightness images, deļ¬cits are evident in
to the E and NE. The SW portion of the excess emis- a pressure-residual map after subtracting oļ¬ a model of
sion was shown in LaganĀ“ et al. (2010) using a shorter
a the average pressure distribution. The deļ¬cits are seen to
Chandra exposure, and in de Plaa et al. (2010) using the N and S of the cluster center, in line with the current
a deep XMM-Newton observation. The spiral structure axis of the radio lobes. Each of these bubbles could inject
was not seen, however, before this very deep Chandra ob- up to 1 Ć 1060 erg into the intracluster medium.
servation. LaganĀ“ et al. presented several residual Chan-
a
dra images of cool core clusters, and noted that A2052
was an exception in not exhibiting a spiral feature in the Support for this work was provided by the National
available data, and de Plaa et al. described the SW ex- Aeronautics and Space Administration, through Chandra
cess as a cold front. Here, in addition to exhibiting an Award Number GO9-0147X. Basic research in radio as-
excess in surface brightness on a 2D model-subtracted tronomy at the Naval Research Laboratory is supported
Chandra image, the brightness distribution is conļ¬rmed by 6.1 Base funding. SWR was supported in part by the
using surface brightness proļ¬les in diļ¬erent sectors across Chandra X-ray Center through NASA contract NAS8-
the image. The spiral is also shown to contain gas cooler 03060. We thank Frazer Owen for useful discussions.
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9. Very Deep Chandra Observation of A2052 9
TABLE 1
Chandra X-ray Observations
Obs ID Date Roll Angle Data Mode Exp
(deg) (ksec)
890 2000-09-03 265.1 FAINT 37.23
5807 2006-03-24 98.9 VFAINT 128.63
10477 2009-06-05 221.2 VFAINT 62.03
10478 2009-05-25 208.2 VFAINT 120.67
10479 2009-06-09 217.1 VFAINT 65.76
10480 2009-04-09 112.2 VFAINT 20.15
10879 2009-04-05 112.2 VFAINT 82.21
10914 2009-05-29 208.2 VFAINT 39.36
10915 2009-06-03 221.2 VFAINT 15.16
10916 2009-06-11 217.1 VFAINT 35.47
10917 2009-06-08 217.1 VFAINT 55.99
TABLE 2
VLA Radio Observations
Obs. Code Date VLA Conļ¬guration Frequency Bandwidth Duration
(MHz) (MHz) (hours)
AS355 1988-11-30 A 4835.1/4885.1 50/50 3.0
AS355 1989-03-30 B 4835.1/4885.1 50/50 2.4
AS355 1989-06-26 C 4835.1/4885.1 50/50 2.6
AS355 1988-11-30 A 1464.9/1514.9 50/50 3.0
AS355 1989-03-30 A 1464.9/1514.9 50/50 2.1
10. 10 Blanton et al.
20:00.0
15:00.0
10:00.0
05:00.0
Declination
7:00:00.0
55:00.0
6:50:00.0
45:00.0
30.0 15:17:00.0 30.0 16:00.0 15:30.0
Right ascension
Fig. 1.ā Chandra ACIS image of A2052 in the 0.3 ā 10.0 keV band showing all CCD chips used in the analysis (the S4 chip was excluded)
and illustrating the diļ¬erent roll angles used in the observations.
11. Very Deep Chandra Observation of A2052 11
Fig. 2.ā Unsmoothed Chandra image in the 0.3 ā 2.0 keV band of the central region of A2052. The image reveals detailed structure
related to the interaction of the AGN with the ICM, with important features labeled.
12. 12 Blanton et al.
Fig. 3.ā Three-color Chandra image of A2052. Red is 0.3 ā 1.0 keV, green is 1.0 ā 3.0 keV, and blue is 3.0 ā 10.0 keV. Cavities are
visible to the north and south of the AGN, surrounded by bright rims. Exterior to the bright rims, a slightly N-S elliptical shock is seen
with hard (blue) emission.
13. Very Deep Chandra Observation of A2052 13
ā² ā²
Fig. 4.ā Composite Chandra X-ray (red), VLA 4.8 GHz (blue), and SDSS r-band (green) 6. 6 Ć 5. 8 image of Abell 2052.
14. 14 Blanton et al.
ā²ā²
Fig. 5.ā Chandra image in the 0.3 ā 10.0 keV band, smoothed with a 1. 5 radius Gaussian, with contours of optical r-band emission
from the SDSS superposed.
15. Very Deep Chandra Observation of A2052 15
Fig. 6.ā Unsharp-masked Chandra 0.3 ā 10.0 keV image of A2052 with 4.8 GHz radio contours superposed. Radio emission ļ¬lls X-ray
cavities to the N and S, as well as outer cavities to the NW, S-SE, and E. The cavities are surrounded by X-ray bright rims. A ļ¬lament
extends into the N cavity, and a narrow ļ¬lament surrounds the NW hole. Ripple-like features are seen surrounding the cluster center,
corresponding to weak shocks.
16. 16 Blanton et al.
ā²
Fig. 7.ā Residual image in the 0.3 ā 2 keV band of the central 5. 66 (240 kpc) radius region of A2052 resulting from the subtraction of
ā²ā²
a 2D beta model. The image has been smoothed with a 7. 38 Gaussian. In addition to the bubble rims seen in the center of the image, on
larger scales, a spiral is visible extending from the SW to the NE. The linear feature in the SW is a chip-edge artifact.
17. Very Deep Chandra Observation of A2052 17
Fig. 8.ā High-resolution temperature map of the central region of A2052 with X-ray surface brightness contours in the 0.3 ā 10.0
keV range superposed. The scale bar is kT in units of keV. The rims surrounding the X-ray cavities are cool, and the coolest regions, in
projection, are coincident with the brightest regions of the rims.
18. 18 Blanton et al.
Fig. 9.ā HĪ± contours from McDonald et al. (2010) superposed onto the central portion of the high-resolution temperature map from
Fig. 8. The coolest regions seen in the X-ray are coincident with emission in HĪ±, representing gas with T ā 104 K. The scale bar is kT in
units of keV.
19. Very Deep Chandra Observation of A2052 19
ā²ā²
Fig. 10.ā Chandra image in the 0.3 ā 10.0 keV band, smoothed with a 1. 5 radius Gaussian, and superposed with contours of HĪ±
emission (McDonald et al. 2010). The X-ray brightest regions in the cluster center show excellent correspondence with the HĪ± emission.
20. 20 Blanton et al.
Fig. 11.ā Pseudo-pressure map of the central region of A2052 with X-ray surface brightness contours in the 0.3 ā 10.0 keV range
superposed. A region of high pressure is seen surrounding the cluster center, outside of the bubble rims, and coincident with the inner
shock feature.
21. Very Deep Chandra Observation of A2052 21
Fig. 12.ā Temperature map using a minimum of 10000 background-subtracted counts for each spectral ļ¬t. Contours of residual surface
brightness showing the spiral feature are superposed. The spiral traces out a region of cooler temperatures. The scale bar is kT in units of
keV. Errors range from 1% in the inner regions to 5% in the outskirts of the map. Holes to the far S and SW are excluded point source
regions.
22. 22 Blanton et al.
Fig. 13.ā Temperature map with the same f.o.v. as Fig. 12, but at higher resolution and using a minimum of 2000 background-subtracted
counts for each spectral ļ¬t. The map contains results from more than 80000 spectral ļ¬ts. The scale bar is kT in units of keV. Errors range
from 2% in the cluster center to 14% in the outer parts of the frame.
23. Very Deep Chandra Observation of A2052 23
Fig. 14.ā Pseudo-pressure map using the spectral ļ¬ts that resulted in the temperature map in Fig. 13. As in Fig. 11, the slightly N-S
elliptical region corresponding to the inner shock is seen. There is no evidence for a region of pressure that corresponds with the spiral
feature seen in Fig. 7.
24. 24 Blanton et al.
Fig. 15.ā Zoomed-in view of the pseudo-pressure map shown in Fig. 14 with X-ray surface brightness contours superposed. The ļ¬rst
inner jump in surface brightness traces out a jump in pressure, and the second inner surface brightness jump traces out a region of enhanced
pressure.
25. Very Deep Chandra Observation of A2052 25
Fig. 16.ā Pseudo-entropy map with excess surface brightness contours (after 2D beta model subtraction) superposed. There is an overall
decrease in entropy towards the cluster center and the sprial feature is conicident with low entropy structure in the map.
26. 26 Blanton et al.
Fig. 17.ā Projected abundance map with contours of the spiral excess superposed. A region of high metallicity is coincident with the
SW portion of the spiral. Abundances shown are relative to solar. The region of apparent high abundance in the NW bubble rim is at
least partly the result of ļ¬tting a one-temperature model to the projected multi-temperature gas in this area. Errors range from 5% in the
inner regions to 23% in the outskirts of the frame, with the majority of the errors at the 10 ā 15% level across the map.
27. Very Deep Chandra Observation of A2052 27
kT (keV) 4 NE
3
2
1
ne (cm )
ā3
0.01
dyn cm )
ā2
10
ā11
P (x 10
10 100
Radius (arcsec)
Fig. 18.ā Deprojected temperature proļ¬le, and proļ¬les of density and pressure for the NE sector. Positions of the inner shocks are
marked with dashed lines. A clear rise in temperature and pressure is seen inside the innermost shock.
28. 28 Blanton et al.
ā²
Fig. 19.ā Residual image in the 0.3 ā 2 keV band of the central 5. 66 (240 kpc) radius region of A2052 resulting from the subtraction of
ā²ā²
a 2D beta model and smoothed with a 7. 38 Gaussian. Superposed on the image are the SW, NE, and NW sectors from which the surface
brightness and temperature proļ¬les shown in Figs. 18, 20, 21, 22, and 23 were extracted.
29. Very Deep Chandra Observation of A2052 29
NW
NE
SW
1
Surface Brightness (ct/s/arcmin )
2
0.1
10 100
Radius (arcsec)
Fig. 20.ā Surface brightness proļ¬les in the 0.3 ā 10 keV band corresponding to the sectors shown in Fig. 19. Clear excesses are seen in
the regions of surface brightness enhancement associated with the spiral feature in Figs. 7 and 19. For the SW, the excess extends from
ā 60ā²ā² ā 195ā²ā² , while for the NE, the excess is seen at radii beyond ā 110ā²ā² .
30. 30 Blanton et al.
4.5
4
3.5
3 NW
kT (keV)
SW
2.5
2
1.5
1
0 50 100 150 200 250 300
Radius (arcsec)
Fig. 21.ā Projected temperature proļ¬les for the SW and NW sectors shown in Fig. 19. The SW sector corresponds with the bright,
inner, spiral region, while the NW sector is the non-spiral, comparison region. The SW spiral excess corresponds with regions of cooler
temperature in the radial range ā 60ā²ā² ā 140ā²ā² . The proļ¬les converge beyond ā 140ā²ā² .
31. Very Deep Chandra Observation of A2052 31
4.5
4
3.5
3 NW
kT (keV)
NE
2.5
2
1.5
1
0 50 100 150 200 250 300
Radius (arcsec)
Fig. 22.ā Projected temperature proļ¬les for the NE and NW sectors shown in Fig. 19. The NE sector corresponds with the outer spiral
region, while the NW sector is the non-spiral, comparison region. Cooler temperatures are seen associated with the NE spiral excess (radii
> 160ā²ā² ).
32. 32 Blanton et al.
kT (keV) 4 SW
3
2
1
ne (cm )
ā3
0.01
dyn cm )
ā2
10
ā11
P (x 10
10 100
Radius (arcsec)
Fig. 23.ā Proļ¬les of temperature, density, and pressure in the SW sector. Filled circles indicate results from deprojected ļ¬ts. The open
circles show the projected temperature proļ¬le and the pressure proļ¬le derived using the density and the projected temperatures. Dashed
lines show the positions of the ļ¬rst inner shock, the second inner shock / edge, and the cold front / SW spiral edge, going from smaller to
larger radii.
33. Very Deep Chandra Observation of A2052 33
1.4
NE
1.2 SW
1
Abundance (x solar)
0.8
0.6
0.4
0 50 100 150 200 250
Radius (arcsec)
Fig. 24.ā Projected abundance proļ¬les for the SW and NE regions. The dashed line indicates the outer edge of the SW spiral / cold
front. The abundances are higher inside the SW spiral region (from ā 70ā²ā² ā 120ā²ā² ) compared to the corresponding radial region to the NE.
34. 34 Blanton et al.
250
200
Entropy (keV cm )
2
150
100
NE
50 SW
0 50 100 150 200 250
Radius (arcsec)
2/3
Fig. 25.ā Entropy proļ¬les for the SW and NE regions with entropy deļ¬ned as S = kT /ne , and using projected temperatures. The
dashed line indicates the outer edge of the SW spiral. The spiral surface-brigthness excess is very well traced by the entropy structure.
The spiral excess to the SW (r ā 70 ā 150ā²ā² ) corresponds with a region of lower entropy. At larger radii r > 190ā²ā² , the spiral excess in the
NE also is shown to have lower entropy values as compared to the non-spiral region in the SW at these large radii.
35. Very Deep Chandra Observation of A2052 35
Fig. 26.ā Radio spectral index map created using the 1.4 and 4.8 GHz data. Contours of 0.3 ā 10.0 keV X-ray surface brightness are
superposed. The outer bubbles to the NW and SE are ļ¬lled with radio emission with steeper spectral index, consistent with these regions
being inļ¬ated by an earlier outburst of the AGN.
36. 36 Blanton et al.
06:00.0
05:00.0
04:00.0
03:00.0
02:00.0
Declination
01:00.0
7:00:00.0
59:00.0
58:00.0
57:00.0
6:56:00.0
15:17:00.0 50.0 40.0 16:30.0
Right ascension
-8E-05 -6E-05 -4E-05 -2E-05 0 2E-05 4E-05 6E-05
Fig. 27.ā Pressure residual map created by subtracting oļ¬ a 2D beta model ļ¬tted to a pseudo-pressure map with 4.8 GHz radio contours
superposed. The inner shock is seen as a pressure enhancement exterior to the radio lobes. In addition, large deļ¬cits in pressure are seen
to the N and S of the cluster center. These may represent āghost cavitiesā related to an earlier AGN outburst.