This document reports on observations of IDCS J1426.5+3508, a galaxy cluster located at a redshift of 1.75. A Sunyaev-Zeldovich decrement was detected towards this cluster, indicating a total mass of 4.3×1014 solar masses. This makes it the most distant cluster detected via the Sunyaev-Zeldovich effect to date and the most massive cluster found at a redshift greater than 1.4. Despite its rarity, the cluster is not unexpected given cosmological models and the large area surveyed. However, it remains one of the rarest and most extreme clusters discovered and provides insight into the early formation of the most massive clusters.
The discovery of a giant arc associated with the galaxy cluster IDCS J1426.5+3508 at z=1.75 is reported. HST imaging reveals an arc-like object with a length-to-width ratio greater than 10, located near the brightest cluster galaxy. Attempts to measure the redshift of the arc through spectroscopy were unsuccessful. The existence of such a massive, strongly lensing cluster at this early epoch poses challenges for the standard ΛCDM model of structure formation.
Color and albedo_heterogeneity_on_vestaSérgio Sacani
The document summarizes findings from the Dawn spacecraft about the composition and geology of Vesta. It found that Vesta's surface has significant heterogeneity in color and albedo. Spectroscopic data revealed variations in the mineralogy and composition, with the Oppia region showing differences possibly related to mass movements. Craters exposed layers with different mineral and chemical compositions, providing insights into Vesta's complex, stratified crust formed from magmatic processes during planetary differentiation.
- Comet C/2011 N3 (SOHO) was observed by the Solar Dynamics Observatory as it passed through the low solar corona in July 2011.
- The comet survived within the corona until it came within 0.146 solar radii (approximately 100,000 km) of the solar surface, at which point its extreme ultraviolet signal disappeared.
- Before being destroyed, material released from the comet was first seen in absorption against the solar corona, then formed an emission nebula as it interacted with the coronal plasma.
Herschel observations of_the_w3_gmc_clues_to_the_formation_of_clusters_of_hig...Sérgio Sacani
1) Herschel observations of the W3 GMC reveal the most massive and luminous clumps - W3 East, W3 West, and W3 (OH) - which have the highest column densities and ongoing high-mass star formation.
2) The observations suggest a "convergent constructive feedback" scenario where feedback from high-mass stars ensures material availability during cluster formation, leading to a decreasing age and increasing system mass towards the inner regions and possibly the formation of Trapezium-like systems.
3) Feedback plays an active role in accumulating, compressing, and confining material, distinguishing high-from low-mass star formation, though different environmental conditions and triggers could lead to a
This study examines a reservoir of ionized gas in the galactic halo that can sustain star formation in the Milky Way. The authors detect a substantial amount of warm-hot gas in the halo of a star-forming galaxy at z=0.2 through detection of Ne VIII absorption lines. This warm-hot gas reservoir contains as much mass as the galaxy's stars and can replenish its supply of cool gas to sustain star formation over billions of years.
The absolute chronology and thermal processing of solids in the solar protopl...Carlos Bella
CAIs define a brief formation interval corresponding to an age of 4567.30 ± 0.16 million years, whereas chondrules range from 4567.32 ± 0.42 to 4564.71 ± 0.30 million years. U-Pb dating refutes the long-held view of an age gap between CAIs and chondrules, instead indicating chondrule formation started contemporaneously with CAIs and lasted ~3 million years. This timeline is similar to protoplanetary disk lifetimes from astronomy, suggesting CAI and chondrule formation occurred during the evolution of the solar protoplanetary disk.
1) The EPOXI mission flew by comet Hartley 2 in 2010, obtaining over 105 images and spectra.
2) Hartley 2 has an unusually small but very active bi-lobed nucleus with dimensions of 2.33 km and a rotation period of about 18 hours.
3) The nucleus shows substantial differences in volatile composition between its lobes and waist region.
The discovery of a giant arc associated with the galaxy cluster IDCS J1426.5+3508 at z=1.75 is reported. HST imaging reveals an arc-like object with a length-to-width ratio greater than 10, located near the brightest cluster galaxy. Attempts to measure the redshift of the arc through spectroscopy were unsuccessful. The existence of such a massive, strongly lensing cluster at this early epoch poses challenges for the standard ΛCDM model of structure formation.
Color and albedo_heterogeneity_on_vestaSérgio Sacani
The document summarizes findings from the Dawn spacecraft about the composition and geology of Vesta. It found that Vesta's surface has significant heterogeneity in color and albedo. Spectroscopic data revealed variations in the mineralogy and composition, with the Oppia region showing differences possibly related to mass movements. Craters exposed layers with different mineral and chemical compositions, providing insights into Vesta's complex, stratified crust formed from magmatic processes during planetary differentiation.
- Comet C/2011 N3 (SOHO) was observed by the Solar Dynamics Observatory as it passed through the low solar corona in July 2011.
- The comet survived within the corona until it came within 0.146 solar radii (approximately 100,000 km) of the solar surface, at which point its extreme ultraviolet signal disappeared.
- Before being destroyed, material released from the comet was first seen in absorption against the solar corona, then formed an emission nebula as it interacted with the coronal plasma.
Herschel observations of_the_w3_gmc_clues_to_the_formation_of_clusters_of_hig...Sérgio Sacani
1) Herschel observations of the W3 GMC reveal the most massive and luminous clumps - W3 East, W3 West, and W3 (OH) - which have the highest column densities and ongoing high-mass star formation.
2) The observations suggest a "convergent constructive feedback" scenario where feedback from high-mass stars ensures material availability during cluster formation, leading to a decreasing age and increasing system mass towards the inner regions and possibly the formation of Trapezium-like systems.
3) Feedback plays an active role in accumulating, compressing, and confining material, distinguishing high-from low-mass star formation, though different environmental conditions and triggers could lead to a
This study examines a reservoir of ionized gas in the galactic halo that can sustain star formation in the Milky Way. The authors detect a substantial amount of warm-hot gas in the halo of a star-forming galaxy at z=0.2 through detection of Ne VIII absorption lines. This warm-hot gas reservoir contains as much mass as the galaxy's stars and can replenish its supply of cool gas to sustain star formation over billions of years.
The absolute chronology and thermal processing of solids in the solar protopl...Carlos Bella
CAIs define a brief formation interval corresponding to an age of 4567.30 ± 0.16 million years, whereas chondrules range from 4567.32 ± 0.42 to 4564.71 ± 0.30 million years. U-Pb dating refutes the long-held view of an age gap between CAIs and chondrules, instead indicating chondrule formation started contemporaneously with CAIs and lasted ~3 million years. This timeline is similar to protoplanetary disk lifetimes from astronomy, suggesting CAI and chondrule formation occurred during the evolution of the solar protoplanetary disk.
1) The EPOXI mission flew by comet Hartley 2 in 2010, obtaining over 105 images and spectra.
2) Hartley 2 has an unusually small but very active bi-lobed nucleus with dimensions of 2.33 km and a rotation period of about 18 hours.
3) The nucleus shows substantial differences in volatile composition between its lobes and waist region.
The document summarizes findings from studying asteroid 4 Vesta using data from NASA's Dawn spacecraft. It finds that Vesta has experienced a violent collisional history, with large impacts creating steep slopes and resurfacing much of the surface. While no unambiguous volcanic deposits were found, some dark material in impact craters may be from excavated subsurface volcanic features. Smooth ponds found on Vesta are also seen on asteroid Eros and are thought to form from impact ejecta collecting in depressions.
The study examines a post-starburst galaxy outflow using ultraviolet spectroscopy of multiple ions including hydrogen. It finds the outflow extends at least 160,000 light-years from the galaxy and contains a hidden mass of at least 6x10^9 times the mass of our Sun. This challenges previous assumptions about the extent and mass of galaxy outflows, suggesting they may play a larger role in regulating galaxy evolution than thought.
Detection of brown dwarf like objects in the core of ngc3603Sérgio Sacani
This document describes observations of the massive galactic cluster NGC 3603 using the Wide Field Camera 3 on the Hubble Space Telescope. Near-infrared data was obtained using narrow and medium band filters spanning the J and H bands, which are sensitive to the 1.3-1.5μm H2O molecular absorption band unique to brown dwarfs. Nine objects were identified having effective temperatures between 1700-2200K, typical of brown dwarfs, located strongly clustered towards the luminous core of NGC 3603. However, if located at the distance of the cluster, these objects would be too luminous to be normal brown dwarfs. The authors explore the possibility that these objects could represent a new class of stars having
1) Apatite samples from the Grand Canyon basement were analyzed using 4He/3He thermochronometry to constrain the near-surface cooling history associated with canyon incision.
2) Data from eastern Grand Canyon apatites indicate substantial canyon incision by ~70 million years ago, earlier than conventional models suggesting incision began 5-6 million years ago.
3) Similar data from western Grand Canyon provide evidence that it was excavated to within a few hundred meters of its modern depth by ~70 million years ago, challenging the view that the entire canyon was carved only in the last 5-6 million years.
Characterizing interstellar filaments with herschel in ic5146Sérgio Sacani
This document summarizes early results from the Herschel Gould Belt survey of the IC5146 molecular cloud. It reveals a complex network of filaments identified in the cloud, which are shown to be the main sites of prestellar core formation. Analysis of 27 filaments finds that their radial column density profiles fall off with radii as r^-1.5 to r^-2.5. Remarkably, the filaments seem to have a narrow distribution of widths centered around 0.1 pc, in contrast to a broader distribution of central Jeans lengths. This characteristic width corresponds to the sonic scale below which turbulence becomes subsonic, supporting the argument that filaments may form from dissipating large-scale turbulence.
The small blue_straggler_star_population_in_the_dense_galactic_globular_clust...Sérgio Sacani
This document summarizes a study of blue straggler star (BSS) populations in the globular cluster NGC 6752. The study used high-resolution Hubble Space Telescope images of the cluster core and wide-field ground-based images covering the outer regions. A total of 28 BSS candidates were identified in the HST images, and an additional 15 BSS candidates were found in the outer regions from the ground-based images. The radial distribution of BSS will be analyzed to understand the dynamical evolution of the cluster.
This document introduces the VLT-FLAMES Tarantula Survey, which obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud. The survey aims to detect massive binary systems through variations in radial velocities and to characterize the properties of O- and B-type stars, addressing questions about stellar and cluster evolution. Spectral classifications are provided for newly discovered emission-line stars, including a new Wolf-Rayet star. The survey data and reduction procedures are overviewed, and upcoming analyses of the massive star properties are announced.
This document presents observations of ACT-CL J0102−4915, a massive galaxy cluster discovered by the Atacama Cosmology Telescope (ACT) via its strong Sunyaev-Zeldovich signal. Optical and X-ray observations reveal that it is undergoing a major merger between components with a mass ratio of 2:1 at a redshift of 0.87. Chandra X-ray data show significant temperature variations across the cluster from 6.6 keV to 22 keV, indicating a hot, luminous system undergoing a merger. The cluster appears to be an excellent example of a "bullet cluster" system at high redshift.
This document summarizes an X-ray study of the supernova remnant G352.7-0.1 using data from XMM-Newton and Chandra observations. Prior observations revealed G352.7-0.1 has a shell-like radio morphology but center-filled thermal X-ray morphology, classifying it as a mixed-morphology supernova remnant. The new observations confirm the X-ray emission comes from the interior and is dominated by ejecta. Spectra from XMM-Newton are fit by a single thermal component with enhanced silicon and sulfur. Some Chandra spectra require a second thermal component to fit, with solar abundances providing a better physical model. No evidence of overionization was found. A neutron
A 100 parsec elliptical and twisted ring of cold and dense molecular clouds r...Sérgio Sacani
The document summarizes observations from the Herschel satellite that reveal a 100-parsec elliptical and twisted ring of cold, dense molecular clouds orbiting the Galactic Center. The ring has a mass of about 3 million solar masses and semi-major axes of 100 and 60 parsecs. Its major axis is inclined 40 degrees to the plane of the sky and perpendicular to the Galactic Bar. The ring appears to trace stable x2 orbits predicted for the barred Galactic potential.
Rocket and fuse_observations_of_ic405_differential_extinction_and_fluorescent...Sérgio Sacani
The document describes rocket and FUSE observations of the emission/reflection nebula IC 405. The observations show that the ratio of nebular surface brightness to stellar flux (S/F*) increases by about two orders of magnitude towards the blue end of the far-UV bandpass. Scattering models fail to reproduce this "blue rise" effect. FUSE spectroscopy reveals a rich fluorescent molecular hydrogen spectrum north of the star. The observations suggest that uncertainties in nebular geometry and dust clumping are likely responsible for the blue rise, rather than fluorescent H2 emission. If IC 405 was spatially unresolved, it would appear to have less dust extinction than observed.
Delivery of dark_material_to_vesta_via_carbonaceous_chondritic_impactsSérgio Sacani
This document analyzes dark material (DM) observed on the surface of asteroid Vesta by NASA's Dawn spacecraft. Spectral analysis finds the DM has properties similar to carbonaceous chondrite meteorites mixed with Vestan surface materials. Laboratory experiments matching the albedo and absorption bands of DM used mixtures of carbonaceous chondrites and eucrite basalt. Impact modeling suggests the DM was delivered via impacts of carbonaceous chondrite asteroids during the formation of the large Veneneia impact basin on Vesta. This supports the idea that carbonaceous chondrites were an important early source of carbon and volatiles in the solar system.
Deep wide field_and_panchromatic_view_of_47_tuc_and_smc_with_hubbleSérgio Sacani
This document describes a deep imaging survey of the globular cluster 47 Tucanae and the Small Magellanic Cloud conducted with the Hubble Space Telescope. Over 700 images were taken with the ACS and WFC3 instruments in six filters spanning wavelengths from 0.4 to 1.7 microns. The images were combined into ultra-deep stacks to study the faintest stars in 47 Tuc down to 30th magnitude in visible light and 27th magnitude in infrared. The data also provide the deepest view of the lower main sequence of the SMC. Careful photometric and astrometric measurements on the stacks reveal unprecedented color-magnitude diagrams of the stellar populations.
Star formation history_in_the_smc_the_case_of_ngc602Sérgio Sacani
This document summarizes a study of the star formation history in the NGC 602 region of the Small Magellanic Cloud based on Hubble Space Telescope observations. Deep photometry reveals numerous pre-main sequence stars as well as young stars on the main sequence, allowing the study of star formation into recent times. New pre-main sequence stellar evolutionary tracks are presented. A stellar population synthesis code is used to derive the best estimate of the star formation history by comparing observed and synthetic color-magnitude diagrams. The star formation rate in the region has increased over the past tens of Myr, reaching 0.3-0.7×10−3 M☉ yr−1 in the last 2.5 Myr, comparable to
The physical conditions_in_a_pre_super_star_cluster_molecular_cloud_in_the_an...Sérgio Sacani
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.
This document discusses the x-ray crystal structure of the mammalian Shaker family potassium ion channel Kv1.2 determined by the authors. Three key conclusions are presented:
1) The voltage sensors that allow the channel to switch between conductive and nonconductive states are independent domains within the membrane.
2) The voltage sensors perform mechanical work on the pore via the S4-S5 linker helices, positioned to constrict or dilate the pore.
3) In the open conformation, two of the four conserved arginine residues on S4 are on a lipid-facing surface while two are buried within the voltage sensor.
This article reports the detection of two gas clouds with no discernible elements heavier than hydrogen, representing the lowest heavy-element abundance observed in the early universe. One cloud at z=3.4 exhibits a deuterium abundance matching predictions from Big Bang nucleosynthesis, providing direct evidence for the standard cosmological model. The sparse metal enrichment of these clouds implies an inhomogeneous process for transporting heavy elements from galaxies into the surrounding intergalactic medium.
Topography of northern_hemisphere_of_mercury_from_messenger_altimeterSérgio Sacani
The document describes a study that used laser altimetry from the MESSENGER spacecraft to create a topographic model of Mercury's northern hemisphere. The study found that Mercury has a much smaller range of elevations compared to Mars or the Moon, likely due to Mercury's higher density and gravitational acceleration smoothing out topographic features. The model revealed numerous large impact structures that influence the shape of the hemisphere but do not significantly affect the distribution of elevations.
The close circumstellar environment of betelgeuseSérgio Sacani
This document summarizes observations of the red supergiant star Betelgeuse and its circumstellar environment using the VLT/VISIR instrument. Diffraction-limited images were obtained in 6 filters between 7.76-12.81 μm and 2 filters between 17.65-19.50 μm. The images reveal a bright, extended, and complex circumstellar envelope at all wavelengths, pointing to the presence of oxygen-rich dust like silicates. A partial circular shell is observed between 0.5-1.0" from the star, which may correspond to the inner radius of the dust envelope. Several knots and filamentary structures are also identified within the nebula.
The magnetic field of the irregular galaxy ngc 4214Sérgio Sacani
This document summarizes a study of the magnetic field in the irregular galaxy NGC 4214 using radio continuum polarization data from the Very Large Array. The researchers find that the global radio spectrum shows signs of free-free absorption and synchrotron losses. They estimate the magnetic field strength is 30 ± 9.5 μG in the center and 10 ± 3 μG at the edges. They do not detect significant polarization on scales greater than 200 pc and place an upper limit of 8 μG on any uniform field in the galaxy.
Chandra deep observation_of_xdcpj004402033_a_massive_galaxy_cluster_at_z_1_5Sérgio Sacani
Artigo apresenta os resultados obtidos pelo Chandra ao medir com precisão a massa do mais massivo aglomerado de galáxias do universo distante, o Aglomerado Gioiello.
This document summarizes follow-up observations of galaxies selected from WISE as being hyperluminous. The authors observed 14 galaxies at 350-850 μm with SHARC-II and 18 galaxies at 1.1 mm with Bolocam, detecting 9 and 5 galaxies respectively. They also observed 25 targets at 3.6 and 4.5 μm with Spitzer and obtained optical spectra for 12 targets. By combining these data with WISE observations, they constructed mid-IR to millimeter spectral energy distributions that showed hotter dust temperatures than galaxy templates, estimated to be 60-120 K. These galaxies have infrared luminosities over 10^13 solar luminosities and represent an extreme population of luminous, hot dust-ob
The document summarizes findings from studying asteroid 4 Vesta using data from NASA's Dawn spacecraft. It finds that Vesta has experienced a violent collisional history, with large impacts creating steep slopes and resurfacing much of the surface. While no unambiguous volcanic deposits were found, some dark material in impact craters may be from excavated subsurface volcanic features. Smooth ponds found on Vesta are also seen on asteroid Eros and are thought to form from impact ejecta collecting in depressions.
The study examines a post-starburst galaxy outflow using ultraviolet spectroscopy of multiple ions including hydrogen. It finds the outflow extends at least 160,000 light-years from the galaxy and contains a hidden mass of at least 6x10^9 times the mass of our Sun. This challenges previous assumptions about the extent and mass of galaxy outflows, suggesting they may play a larger role in regulating galaxy evolution than thought.
Detection of brown dwarf like objects in the core of ngc3603Sérgio Sacani
This document describes observations of the massive galactic cluster NGC 3603 using the Wide Field Camera 3 on the Hubble Space Telescope. Near-infrared data was obtained using narrow and medium band filters spanning the J and H bands, which are sensitive to the 1.3-1.5μm H2O molecular absorption band unique to brown dwarfs. Nine objects were identified having effective temperatures between 1700-2200K, typical of brown dwarfs, located strongly clustered towards the luminous core of NGC 3603. However, if located at the distance of the cluster, these objects would be too luminous to be normal brown dwarfs. The authors explore the possibility that these objects could represent a new class of stars having
1) Apatite samples from the Grand Canyon basement were analyzed using 4He/3He thermochronometry to constrain the near-surface cooling history associated with canyon incision.
2) Data from eastern Grand Canyon apatites indicate substantial canyon incision by ~70 million years ago, earlier than conventional models suggesting incision began 5-6 million years ago.
3) Similar data from western Grand Canyon provide evidence that it was excavated to within a few hundred meters of its modern depth by ~70 million years ago, challenging the view that the entire canyon was carved only in the last 5-6 million years.
Characterizing interstellar filaments with herschel in ic5146Sérgio Sacani
This document summarizes early results from the Herschel Gould Belt survey of the IC5146 molecular cloud. It reveals a complex network of filaments identified in the cloud, which are shown to be the main sites of prestellar core formation. Analysis of 27 filaments finds that their radial column density profiles fall off with radii as r^-1.5 to r^-2.5. Remarkably, the filaments seem to have a narrow distribution of widths centered around 0.1 pc, in contrast to a broader distribution of central Jeans lengths. This characteristic width corresponds to the sonic scale below which turbulence becomes subsonic, supporting the argument that filaments may form from dissipating large-scale turbulence.
The small blue_straggler_star_population_in_the_dense_galactic_globular_clust...Sérgio Sacani
This document summarizes a study of blue straggler star (BSS) populations in the globular cluster NGC 6752. The study used high-resolution Hubble Space Telescope images of the cluster core and wide-field ground-based images covering the outer regions. A total of 28 BSS candidates were identified in the HST images, and an additional 15 BSS candidates were found in the outer regions from the ground-based images. The radial distribution of BSS will be analyzed to understand the dynamical evolution of the cluster.
This document introduces the VLT-FLAMES Tarantula Survey, which obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud. The survey aims to detect massive binary systems through variations in radial velocities and to characterize the properties of O- and B-type stars, addressing questions about stellar and cluster evolution. Spectral classifications are provided for newly discovered emission-line stars, including a new Wolf-Rayet star. The survey data and reduction procedures are overviewed, and upcoming analyses of the massive star properties are announced.
This document presents observations of ACT-CL J0102−4915, a massive galaxy cluster discovered by the Atacama Cosmology Telescope (ACT) via its strong Sunyaev-Zeldovich signal. Optical and X-ray observations reveal that it is undergoing a major merger between components with a mass ratio of 2:1 at a redshift of 0.87. Chandra X-ray data show significant temperature variations across the cluster from 6.6 keV to 22 keV, indicating a hot, luminous system undergoing a merger. The cluster appears to be an excellent example of a "bullet cluster" system at high redshift.
This document summarizes an X-ray study of the supernova remnant G352.7-0.1 using data from XMM-Newton and Chandra observations. Prior observations revealed G352.7-0.1 has a shell-like radio morphology but center-filled thermal X-ray morphology, classifying it as a mixed-morphology supernova remnant. The new observations confirm the X-ray emission comes from the interior and is dominated by ejecta. Spectra from XMM-Newton are fit by a single thermal component with enhanced silicon and sulfur. Some Chandra spectra require a second thermal component to fit, with solar abundances providing a better physical model. No evidence of overionization was found. A neutron
A 100 parsec elliptical and twisted ring of cold and dense molecular clouds r...Sérgio Sacani
The document summarizes observations from the Herschel satellite that reveal a 100-parsec elliptical and twisted ring of cold, dense molecular clouds orbiting the Galactic Center. The ring has a mass of about 3 million solar masses and semi-major axes of 100 and 60 parsecs. Its major axis is inclined 40 degrees to the plane of the sky and perpendicular to the Galactic Bar. The ring appears to trace stable x2 orbits predicted for the barred Galactic potential.
Rocket and fuse_observations_of_ic405_differential_extinction_and_fluorescent...Sérgio Sacani
The document describes rocket and FUSE observations of the emission/reflection nebula IC 405. The observations show that the ratio of nebular surface brightness to stellar flux (S/F*) increases by about two orders of magnitude towards the blue end of the far-UV bandpass. Scattering models fail to reproduce this "blue rise" effect. FUSE spectroscopy reveals a rich fluorescent molecular hydrogen spectrum north of the star. The observations suggest that uncertainties in nebular geometry and dust clumping are likely responsible for the blue rise, rather than fluorescent H2 emission. If IC 405 was spatially unresolved, it would appear to have less dust extinction than observed.
Delivery of dark_material_to_vesta_via_carbonaceous_chondritic_impactsSérgio Sacani
This document analyzes dark material (DM) observed on the surface of asteroid Vesta by NASA's Dawn spacecraft. Spectral analysis finds the DM has properties similar to carbonaceous chondrite meteorites mixed with Vestan surface materials. Laboratory experiments matching the albedo and absorption bands of DM used mixtures of carbonaceous chondrites and eucrite basalt. Impact modeling suggests the DM was delivered via impacts of carbonaceous chondrite asteroids during the formation of the large Veneneia impact basin on Vesta. This supports the idea that carbonaceous chondrites were an important early source of carbon and volatiles in the solar system.
Deep wide field_and_panchromatic_view_of_47_tuc_and_smc_with_hubbleSérgio Sacani
This document describes a deep imaging survey of the globular cluster 47 Tucanae and the Small Magellanic Cloud conducted with the Hubble Space Telescope. Over 700 images were taken with the ACS and WFC3 instruments in six filters spanning wavelengths from 0.4 to 1.7 microns. The images were combined into ultra-deep stacks to study the faintest stars in 47 Tuc down to 30th magnitude in visible light and 27th magnitude in infrared. The data also provide the deepest view of the lower main sequence of the SMC. Careful photometric and astrometric measurements on the stacks reveal unprecedented color-magnitude diagrams of the stellar populations.
Star formation history_in_the_smc_the_case_of_ngc602Sérgio Sacani
This document summarizes a study of the star formation history in the NGC 602 region of the Small Magellanic Cloud based on Hubble Space Telescope observations. Deep photometry reveals numerous pre-main sequence stars as well as young stars on the main sequence, allowing the study of star formation into recent times. New pre-main sequence stellar evolutionary tracks are presented. A stellar population synthesis code is used to derive the best estimate of the star formation history by comparing observed and synthetic color-magnitude diagrams. The star formation rate in the region has increased over the past tens of Myr, reaching 0.3-0.7×10−3 M☉ yr−1 in the last 2.5 Myr, comparable to
The physical conditions_in_a_pre_super_star_cluster_molecular_cloud_in_the_an...Sérgio Sacani
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.
This document discusses the x-ray crystal structure of the mammalian Shaker family potassium ion channel Kv1.2 determined by the authors. Three key conclusions are presented:
1) The voltage sensors that allow the channel to switch between conductive and nonconductive states are independent domains within the membrane.
2) The voltage sensors perform mechanical work on the pore via the S4-S5 linker helices, positioned to constrict or dilate the pore.
3) In the open conformation, two of the four conserved arginine residues on S4 are on a lipid-facing surface while two are buried within the voltage sensor.
This article reports the detection of two gas clouds with no discernible elements heavier than hydrogen, representing the lowest heavy-element abundance observed in the early universe. One cloud at z=3.4 exhibits a deuterium abundance matching predictions from Big Bang nucleosynthesis, providing direct evidence for the standard cosmological model. The sparse metal enrichment of these clouds implies an inhomogeneous process for transporting heavy elements from galaxies into the surrounding intergalactic medium.
Topography of northern_hemisphere_of_mercury_from_messenger_altimeterSérgio Sacani
The document describes a study that used laser altimetry from the MESSENGER spacecraft to create a topographic model of Mercury's northern hemisphere. The study found that Mercury has a much smaller range of elevations compared to Mars or the Moon, likely due to Mercury's higher density and gravitational acceleration smoothing out topographic features. The model revealed numerous large impact structures that influence the shape of the hemisphere but do not significantly affect the distribution of elevations.
The close circumstellar environment of betelgeuseSérgio Sacani
This document summarizes observations of the red supergiant star Betelgeuse and its circumstellar environment using the VLT/VISIR instrument. Diffraction-limited images were obtained in 6 filters between 7.76-12.81 μm and 2 filters between 17.65-19.50 μm. The images reveal a bright, extended, and complex circumstellar envelope at all wavelengths, pointing to the presence of oxygen-rich dust like silicates. A partial circular shell is observed between 0.5-1.0" from the star, which may correspond to the inner radius of the dust envelope. Several knots and filamentary structures are also identified within the nebula.
The magnetic field of the irregular galaxy ngc 4214Sérgio Sacani
This document summarizes a study of the magnetic field in the irregular galaxy NGC 4214 using radio continuum polarization data from the Very Large Array. The researchers find that the global radio spectrum shows signs of free-free absorption and synchrotron losses. They estimate the magnetic field strength is 30 ± 9.5 μG in the center and 10 ± 3 μG at the edges. They do not detect significant polarization on scales greater than 200 pc and place an upper limit of 8 μG on any uniform field in the galaxy.
Chandra deep observation_of_xdcpj004402033_a_massive_galaxy_cluster_at_z_1_5Sérgio Sacani
Artigo apresenta os resultados obtidos pelo Chandra ao medir com precisão a massa do mais massivo aglomerado de galáxias do universo distante, o Aglomerado Gioiello.
This document summarizes follow-up observations of galaxies selected from WISE as being hyperluminous. The authors observed 14 galaxies at 350-850 μm with SHARC-II and 18 galaxies at 1.1 mm with Bolocam, detecting 9 and 5 galaxies respectively. They also observed 25 targets at 3.6 and 4.5 μm with Spitzer and obtained optical spectra for 12 targets. By combining these data with WISE observations, they constructed mid-IR to millimeter spectral energy distributions that showed hotter dust temperatures than galaxy templates, estimated to be 60-120 K. These galaxies have infrared luminosities over 10^13 solar luminosities and represent an extreme population of luminous, hot dust-ob
Discovery of a_massive_selected_galaxy_clusterSérgio Sacani
This document reports the discovery of a massive galaxy cluster, IDCS J1426+3508, at a redshift of 1.75. Spectroscopic observations from Hubble and Keck confirm the cluster redshift. Archival Chandra X-ray data detect the cluster as an extended X-ray source, implying a mass of 5.6×1014 solar masses. This makes it an exceptionally massive cluster for its high redshift of 1.75. The discovery helps address issues in astrophysics by providing more high-redshift clusters to constrain cosmological parameters and study the evolution of massive galaxies in dense environments.
The first hyper_luminous_infrared_galaxy_discovered_by_wiseSérgio Sacani
This document summarizes the discovery of WISE J181417.29+341224.9 (WISE 1814+3412), the first hyper-luminous infrared galaxy (LIR > 1013 L⊙) 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 and has a star formation rate of ~300M⊙ yr−1, accounting for <10% of the bolometric luminosity. An obscured AGN combined with starburst and
The first hyper_luminous_infrared_galaxy_discovered_by_wiseSérgio Sacani
This document summarizes the discovery of WISE J181417.29+341224.9 (WISE 1814+3412), the first hyper-luminous infrared galaxy (LIR > 1013 L⊙) 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 ~300M⊙ yr−1, accounting for <10% of the total luminosity. An obscured
This document summarizes a study that identified 195 compact elliptical galaxies across different environments using data from optical and ultraviolet sky surveys. The researchers constructed the sample by selecting galaxies that were outliers from the universal color-magnitude relation and had small sizes and high stellar velocity dispersions based on spectral modeling. They found that 7 of the galaxies were isolated, not belonging to any known galaxy groups. For these isolated galaxies, the researchers identified possible host galaxies located up to 3.3 Mpc away. The stellar populations of the isolated compact elliptical galaxies were found to be similar to those in galaxy groups and clusters, suggesting a common formation mechanism.
Our deep, wide-field imaging of M101 and its surrounding environment reveals:
1) M101's disk extends to nearly 25 arcminutes (50 kpc), three times the measured optical radius, with an asymmetric plume of light to the northeast following the extended HI disk.
2) This outer plume has very blue colors, suggesting a somewhat evolved young stellar population, while another redder spur is detected to the east.
3) No evidence is found of very extended tidal tails around M101 or its companions despite signs of past interactions shaping M101's asymmetry.
4) The detection of starlight at such large radii allows studying the stellar populations and star formation histories in M101's outer disk
This document summarizes evidence that a galaxy at a redshift of 1.35 contains three accreting black holes. Hubble Space Telescope observations reveal the galaxy has a clumpy morphology with four distinct components, labeled A, B, C, and D. Spectroscopy of the three brightest components (A, B, and C) shows high [O iii]/Hβ line ratios indicative of active galactic nuclei. This provides evidence that each of the three components contains a rapidly growing black hole of mass 106–107 solar masses. The black holes could have formed via early mergers or grown more recently within the galaxy.
A LUMINOUS Be+WHITE DWARF SUPERSOFT SOURCE IN THE WING OF THE SMC: MAXI J0158...Carlos Bella
This document summarizes a study of the X-ray source MAXI J0158-744, which was detected by the MAXI instrument in November 2011. It exhibited an unusually bright and brief X-ray flare with a luminosity exceeding 10^39 erg/s, approaching ultraluminous X-ray source levels. Follow-up observations with Swift and other instruments over subsequent months found the source had a very soft X-ray spectrum characteristic of a supersoft source. Optical spectra of the counterpart revealed emission and absorption features consistent with a B1/2IIIe spectral type star in the Small Magellanic Cloud. The authors propose MAXI J0158-744 is a luminous supersoft source associated with
Star formation at the smallest scales; A JWST study of the clump populations ...Sérgio Sacani
We present the clump populations detected in 18 lensed galaxies at redshifts 1 to 8.5 within the lensing cluster field SMACS0723.
The recent JWST Early Release Observations of this poorly known region of the sky have revealed numerous point-like sources
within and surrounding their host galaxies, undetected in the shallower HST images. We use JWST multiband photometry and
the lensing model of this galaxy cluster to estimate the intrinsic sizes and magnitudes of the stellar clumps. We derive optical
restframe effective radii from <10 to hundreds pc and masses ranging from ∼ 105
to 109 M, overlapping with massive star
clusters in the local universe. Clump ages range from 1 Myr to 1 Gyr. We compare the crossing time to the age of the clumps
and determine that between 45 and 60 % of the detected clumps are consistent with being gravitationally bound. On average,
the dearth of Gyr old clumps suggests that the dissolution time scales are shorter than 1 Gyr. We see a significant increase in the
luminosity (mass) surface density of the clumps with redshift. Clumps in reionisation era galaxies have stellar densities higher
than star clusters in the local universe. We zoom in into single galaxies at redshift < 6 and find for two galaxies, the Sparkler and
the Firework, that their star clusters/clumps show distinctive colour distributions and location surrounding their host galaxy that
are compatible with being accredited or formed during merger events. The ages of some of the compact clusters are between
1 and 4 Gyr, e.g., globular cluster precursors formed around 9-12 Gyr ago. Our study, conducted on a small sample of galaxies,
shows the potential of JWST observations for understanding the conditions under which star clusters form in rapidly evolving
galaxies.
This document reports on spectroscopic observations of z-band dropout galaxy candidates in the NTT Deep Field. Two galaxies are confirmed to be at redshift ~6.7 based on detected Lyman-alpha emission lines. For NTTDF-474, a faint line is detected at 9270 Angstroms, identified as Lyman-alpha at z=6.623. For NTTDF-1917, an emission line is seen at 8415 Angstroms, which may be Lyman-alpha or H-beta. No significant features were found for the other candidates. These results provide further evidence of galaxy populations in the early universe approaching the epoch of reionization.
Candels the correlation_between_galaxy_morphology_and_star_formation_activity...Sérgio Sacani
This document summarizes a study investigating the relationship between galaxy morphology and star formation activity at z ~ 2 using a sample of 1,671 galaxies from CANDELS images in the GOODS-South field. The sample separates into massive, red, passive galaxies and less massive, blue, star-forming galaxies, correlating well with morphological properties. Star-forming galaxies show a variety of morphologies including clumpy structures and bulges mixed with faint disks, while passive galaxies often have compact morphologies resembling local spheroids. Similar trends are seen in local massive galaxies, suggesting the Hubble sequence was in place by z ~ 2.
This document presents a study characterizing active galactic nuclei (AGN) selected using mid-infrared colors from the Wide-field Infrared Survey Explorer (WISE). The authors find that a simple color criterion of W1-W2 ≥ 0.8 selects AGN with high reliability to a depth of W2 ∼ 15.0, identifying over 60 AGN candidates per square degree. This WISE selection method is effective at identifying both obscured and unobscured AGN. Using deep data in the COSMOS field, the authors explore the properties and redshift distribution of WISE-selected AGN candidates, finding the selection identifies 78% of AGN identified by previous Spitzer studies.
The most luminous_galaxies_discovered_by_wiseSérgio Sacani
This document presents a sample of 20 extremely luminous galaxies discovered by the Wide-field Infrared Survey Explorer (WISE). Five of these galaxies have infrared luminosities exceeding 1014 solar luminosities, the highest infrared luminosity threshold yet observed. They were selected using criteria requiring weak or no detection in the first two WISE bands but strong detections in the third and fourth bands. Spectral energy distribution modeling suggests their high luminosities are powered by obscured active galactic nuclei with hot dust temperatures around 450 Kelvin. The existence of such luminous galaxies at redshifts above 3 provides constraints on the early growth of supermassive black holes through rapid accretion.
This document summarizes the results of a deep near-infrared survey of the Carina Nebula complex using the HAWK-I instrument on the VLT. The survey imaged an area of 0.36 square degrees down to magnitudes of J=23, H=22, and Ks=21, detecting over 600,000 infrared sources. Color-magnitude diagrams of the sources were analyzed to determine properties of the low-mass stellar population such as ages and masses. The survey found that about 3200 sources have masses above 1 solar mass, consistent with expectations from the initial mass function. It also found that about half of the young stars in Carina are in a widely distributed, non-clustered configuration. Six
1. VFTS 682 is a very massive star located 29 pc in projection from the young massive cluster R136 in the Tarantula Nebula of the LMC.
2. Spectral modeling finds it has an unusually high luminosity of log(L/L) = 6.5, corresponding to a present-day mass of ~150 solar masses.
3. Its isolation and mass pose the question of whether it formed in situ, which would profoundly impact theories of massive star formation, or if it was ejected from R136, making it the most massive runaway star known.
Clash new multiple-images constraining the inner mass profile of macs j1206....Sérgio Sacani
The document summarizes a study of the galaxy cluster MACS J1206.2-0847 using Hubble Space Telescope observations. The observations revealed 47 new multiply-lensed images of 12 distant galaxies, enabling an accurate analysis of the inner mass profile. The analysis found an inner slope of -0.55 ± 0.1, typical of relaxed clusters. For a source at redshift 2.5, the critical curve encompasses an effective Einstein radius of 28 ± 3 arcseconds, corresponding to a projected mass of 1.34 ± 0.15 × 1014 solar masses. The high mass and redshift of the cluster provide a stringent test of the standard cosmological model.
This document summarizes a study that uses cosmological simulations to model the formation of stellar halos around galaxies via the tidal disruption of accreted dwarf galaxies. The simulations follow the dynamical evolution and disruption of satellites from high redshift in a fully cosmological setting. The simulations produce stellar halos with masses and density profiles consistent with observations of the Milky Way and M31. The stellar halos show complex structures composed of well-mixed components, tidal streams, shells, and other substructures rather than smooth distributions.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ 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 × 10−8 photons cm−2
s
−1
. 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 behaviour of_dark_matter_associated_with_4_bright_cluster_galaxies_in_the...Sérgio Sacani
The document presents new Hubble Space Telescope imaging and Very Large Telescope integral-field spectroscopy of galaxy cluster Abell 3827. It finds that each of the four central galaxies in the cluster's 10 kpc core retains an associated massive dark matter halo. At least one galaxy is offset from its dark matter halo, with an offset of 1.62+0.50−0.47 kpc, within the uncertainties of mass modeling and statistical errors. If interpreted as evidence for self-interacting dark matter, this offset implies a dark matter self-interaction cross-section of (1.7 ± 0.7)×10−4 cm2/g.
Similar to Measurements of a_massive_galaxy_cluster (20)
Compositions of iron-meteorite parent bodies constrainthe structure of the pr...Sérgio Sacani
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.
Signatures of wave erosion in Titan’s coastsSérgio Sacani
The shorelines of Titan’s 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 Titan’s 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 Titan’s 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.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
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 ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. 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 W1−W2 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 ∼ 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 ∼ 106M⊙ 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: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
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 SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
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 R–I spectral index by 1.0 ±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.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
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 Brγ 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 H−K and K−L 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 (≈15yr). 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 ± 20◦, 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 holes– stars: formation– Galaxy: center– galaxies: star formation
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
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 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 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.
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
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 ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
The binding of cosmological structures by massless topological defectsSérgio Sacani
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.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 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 1–2 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
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
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.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s 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 Io’s 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 Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
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 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” 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 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. 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 ∼ 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 IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
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.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
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 » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 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.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
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 ± 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 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 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.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
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 (< 0.00003–0.002). 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.
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Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
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 Earth’s 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 (F⨀;
approximately +2.5% W m−2 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 mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
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system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
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Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
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1. ApJ, in press
Preprint typeset using L TEX style emulateapj v. 5/2/11
A
IDCS J1426.5+3508: SUNYAEV–ZEL’DOVICH MEASUREMENT OF A MASSIVE IR-SELECTED CLUSTER
AT Z = 1.75
M. Brodwin,1,2 A. H. Gonzalez,3 S. A. Stanford,4,5 T. Plagge,6,7 D. P. Marrone,8 J. E. Carlstrom6,7,9 A. Dey,10
P. R. Eisenhardt,11 C. Fedeli,3 D. Gettings,3 B. T. Jannuzi,10 M. Joy,12 E. M. Leitch,6,7 C. Mancone,3
G. F. Snyder,2 D. Stern,11 and G. Zeimann4
ApJ, in press
arXiv:1205.3787v1 [astro-ph.CO] 16 May 2012
ABSTRACT
We report 31 GHz CARMA observations of IDCS J1426.5+3508, an infrared-selected galaxy cluster
at z = 1.75. A Sunyaev–Zel’dovich decrement is detected towards this cluster, indicating a total mass
of M200,m = (4.3 ± 1.1) × 1014 M⊙ in agreement with the approximate X-ray mass of ∼ 5 × 1014 M⊙ .
IDCS J1426.5+3508 is by far the most distant cluster yet detected via the Sunyaev–Zel’dovich effect,
and the most massive z ≥ 1.4 galaxy cluster found to date. Despite the mere ∼ 1% probability
of finding it in the 8.82 deg2 IRAC Distant Cluster Survey, IDCS J1426.5+3508 is not completely
unexpected in ΛCDM once the area of large, existing surveys is considered. IDCS J1426.5+3508
is, however, among the rarest, most extreme clusters ever discovered, and indeed is an evolutionary
precursor to the most massive known clusters at all redshifts. We discuss how imminent, highly
sensitive Sunyaev–Zel’dovich experiments will complement infrared techniques for statistical studies
of the formation of the most massive galaxy clusters in the z > 1.5 Universe, including potential
precursors to IDCS J1426.5+3508.
Subject headings: galaxies: clusters: individual (IDCS J1426.5+3508) — galaxies: clusters: intra-
cluster medium — galaxies: evolution — cosmology: observations — cosmology:
cosmic background radiation
1. INTRODUCTION 2010; Holz and Perlmutter 2010; Mortonson et al. 2011;
As the most massive collapsed objects, galaxy clusters Cay´n et al. 2011; Hoyle et al. 2011; Enqvist et al. 2011;
o
provide a sensitive probe of the cosmological parameters Foley et al. 2011; Williamson et al. 2011; Hotchkiss 2011;
that govern the dynamics of the Universe. Traditional Paranjape et al. 2011). These rare, massive clusters were
cluster cosmology experiments constrain these parame- all identified from their hot intracluster medium (ICM),
ters by comparing predicted cluster mass functions with whether via X-ray emission or from prominent Sunyaev–
observed cluster counts (for a review, see Allen et al. Zel’dovich (SZ) decrements.
2011). Conversely, the most successful method for discov-
The recent discovery of a handful of very massive, ering large samples of high redshift galaxy clusters,
high redshift (z > 1) galaxy clusters (Rosati et al. 2009; out to at least z = 1.5, is via infrared selection
Brodwin et al. 2010; Foley et al. 2011) has prompted (e.g., Eisenhardt et al. 2008; Muzzin et al. 2008). For
several studies of the power of individual massive, rare instance, the Spitzer/IRAC Shallow Cluster Survey
clusters to probe the physics of inflation, in particular (ISCS, Eisenhardt et al. 2008), which employs a full
non-Gaussianity in the density fluctuations that seed three-dimensional wavelet search technique on a 4.5µm-
structure formation (Dalal et al. 2008; Brodwin et al. selected, stellar mass-limited galaxy sample, has dis-
covered 116 candidate galaxy clusters and groups at
1 Department of Physics and Astronomy, University of z > 1. More than 20 of these have now been spectro-
Missouri, 5110 Rockhill Road, Kansas City, MO 64110 scopically confirmed at 1 < z < 1.5 (Stanford et al. 2005;
2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Elston et al. 2006; Brodwin et al. 2006; Eisenhardt et al.
Street, Cambridge, MA 2008; Brodwin et al. 2011).
3 Department of Astronomy, University of Florida,
Gainesville, FL 32611
The cosmological importance of individual galaxy clus-
4 Department of Physics, University of California, One Shields ters depends primarily on their rarity, with the most
Avenue, Davis, CA 95616 massive clusters at any redshift providing the most lever-
5 Institute of Geophysics and Planetary Physics, Lawrence
age. The maximum predicted cluster mass increases with
Livermore National Laboratory, Livermore, CA 94550
6 Kavli Institute for Cosmological Physics, University of time due to the growth of structure. Consequently, clus-
Chicago, Chicago, IL 60637 ters with moderate masses, by present-day standards,
7 Department of Astronomy and Astrophysics, University of
of a few ×1014 M⊙ are cosmologically interesting at
Chicago, Chicago, IL 60637 the highest redshifts (e.g., z > 1.5). Only one such
8 Steward Observatory, University of Arizona, 933 North
Cherry Avenue, Tucson, AZ 85721 cluster, XDCP J0044.0-2033 at z = 1.58 (Santos et al.
9 Dept. of Physics/Enrico Fermi Institute, University of 2011), has been found to date, although at such a high
Chicago, Chicago, IL 60637
10 NOAO, 950 North Cherry Avenue, Tucson, AZ 85719
redshift its LX –based mass is quite uncertain. The
11 Jet Propulsion Laboratory, California Institute of Technol- most sensitive, large angle, ICM-based cluster survey to
ogy, Pasadena, CA 91109 date, the 2500 deg2 South Pole Telescope Survey (SPT;
12 Department of Space Science, VP62, NASA Marshall Space Carlstrom et al. 2011), would only be able to detect such
Flight Center, Huntsville, AL 35812, USA high redshift clusters if they were more massive than
2. 2 Brodwin et al.
≈ 3×1014 M⊙ (Vanderlinde et al. 2010; Andersson et al. nosity of L0.5-2keV = (5.5 ± 1.2) × 1044 erg/s. Using the
2011). A population of such high-redshift clusters, if M500 –LX scaling relation of Vikhlinin et al. (2009) and
massive enough, could provide a powerful opportunity the Duffy et al. (2008) mass–concentration relation, this
to study the physics of the early Universe and, in par- corresponds to a mass of M200,c ≃ 5.6×1014 M⊙ (S12)13 .
ticular, to either confirm or falsify the predictions of the The HST/ACS and WFC3 color image, along with the
ΛCDM paradigm. They would also be invaluable probes X-ray detection (yellow contours) are shown in the lower
of the early formation of massive galaxies in the richest panel of Figure 1.
environments. While IDCS J1426.5+3508 appears from the X-ray
To extend the ISCS infrared-selected cluster sample to data to be impressively massive, particularly at such an
the z > 1.5 regime, we carried out the Spitzer Deep, extreme redshift, the X-ray luminosity is based on only
Wide–Field Survey (SDWFS, Ashby et al. 2009), which 54 cluster X-ray photons. Further, it relies on a high-
quadrupled the Spitzer/IRAC exposure time, leading to scatter mass proxy, the M500,c -LX relation, which is only
a survey more than a factor of 2 deeper than the original calibrated at low (z < 1) redshift. The uncertainty of this
IRAC Shallow Survey (Eisenhardt et al. 2004). A new X-ray mass estimate is at least ∼ 40%.
cluster search, the Spitzer/IRAC Distant Cluster Survey
(IDCS), to be described in detail in forthcoming papers, 3. DATA
was carried out using new photometric redshifts calcu- 3.1. Sunyaev Zel’dovich Observations
lated for the larger, deeper SDWFS sample. Cluster
IDCS J1426.5+3508 at z = 1.75 (Stanford et al. 2012, IDCS J1426.5+3508 was observed with the SZA, an 8-
hereafter S12) is the first of the new high–redshift IDCS element radio interferometer optimized for measurements
clusters to be spectroscopically confirmed. of the SZ effect. During the time in which the data were
In this paper we report the robust detection of the obtained, the array was sited at the Cedar Flat location
SZ decrement associated with IDCS J1426.5+3508 in described in Culverhouse et al. (2010), and was in the
31 GHz interferometric data taken with the Sunyaev– “SL” configuration. In this configuration, six elements
Zel’dovich Array (SZA), a subarray of the Com- comprise a compact array sensitive to arcminute-scale SZ
bined Array for Research in Millimeter-wave Astron- signals, and two outrigger elements provide simultaneous
omy (CARMA). This is by far the most distant clus- discrimination for compact radio source emission. The
ter yet detected in the SZ effect, a consequence of the compact array and outrigger baselines provide baseline
fact that IDCS J1426.5+3508 is the most massive clus- lengths of 0.35-1.3 kλ and 2-7.5 kλ, respectively.
ter yet discovered at z > 1.4. In §2 we briefly describe The cluster was observed for four sidereal passes on
the discovery of cluster IDCS J1426.5+3508. In §3 we nights ranging over UT 2011 June 9–29, for a total
present the CARMA observations and reductions, and of 6.24 hours of unflagged, on-source integration time.
describe the measurement of the Comptonization and Data were obtained in an 8 GHz passband centered at
mass of IDCS J1426.5+3508. We also discuss various 31 GHz. The resulting noise level achieved by the short
systematic uncertainties present in our analysis. In §4, (SZ-sensitive) baselines was 0.29 mJy/beam, or 22 µKRJ
we calculate the likelihood of having found this clus- with a synthesized beam of 118′′ × 143′′ . For the long
ter, given our survey selection function, in a standard baselines, the noise level achieved was 0.29 mJy/beam
′′ ′′
ΛCDM cosmology. In §5, we place IDCS J1426.5+3508 in a 19. 9 × 14. 4 beam. The data were reduced us-
in an evolutionary context, finding that it is a pre- ing the Miriad software package (Sault et al. 1995), and
cursor to the most massive known clusters at all red- the absolute calibration was determined using periodic
shifts. In §6 we discuss our results in light of current measurements of Mars calibrated against the Rudy et al.
and upcoming SZ surveys. We present our conclusions (1987) model. A systematic uncertainty of 5% has been
in §7. In this paper, we adopt the WMAP7 cosmology applied to the SZ measurements due to the uncertainty
of (ΩΛ , ΩM , h) = (0.728, 0.272, 0.704) of Komatsu et al. in the absolute calibration. The SZA map is shown in
(2011). Except where otherwise specified (in §2 and the upper left panel of Figure 1.
§3.2), we use a cluster mass (M200,m ) defined as the mass
enclosed within a spherical region of mean overdensity 3.2. Comptonization and Mass of IDCS J1426.5+3508
200 × ρmean , where ρmean is the mean matter density on To determine the properties of IDCS J1426.5+3508
large scales at the redshift of the cluster. from the SZA data, we make use of the fact that the
integrated Compton y-parameter scales with total mass.
2. CLUSTER IDCS J1426.5+3508
Assuming a spherically symmetric pressure distribution
IDCS J1426.5+3508, first reported in S12, was discov- within the cluster, the integrated y-parameter is given
ered in the IDCS as a striking three-dimensional over- by
density of massive galaxies with photometric redshifts 2 σT
at zphot ≈ 1.8 (Figure 1, upper right panel). Follow- Y DA = P (r)dV, (1)
me c2
up spectroscopy, with HST/WFC3 in the infrared and
Keck/LRIS in the optical, identified seven robust spec- where DA is the angular diameter distance, σT is the
troscopic members at z = 1.75 and ten additional likely Thomson cross-section of an electron, me is the electron
members with less certain redshifts. The HST data also mass, c is the speed of light, P (r) is the pressure profile,
revealed the presence of a strong gravitational arc, the and the integral is over a spherical volume centered on
analysis and implications of which are discussed in a com- the cluster (see, e.g., Marrone et al. 2011). The pressure
panion paper (Gonzalez et al. 2012).
IDCS J1426.5+3508 is also detected in shallow Chan- 13 In S12 the mass is measured with respect to a critical over-
dra data from Murray et al. (2005), with an X-ray lumi- density, rather than mean overdensity we use in this paper.
3. IDCS J1426.5+3508: SZ Measurement of a Massive IR-selected Cluster at z = 1.75 3
Figure 1. Upper left: 12.8′ × 12.8′ SZA mm-wave map showing the SZ decrement of IDCS J1426.5+3508. The flux scale in mJy/beam is
shown to the right of the map, and the FWHM of the CLEAN beam is shown in the lower left corner. Upper right: A 5′ × 5′ BW R[4.5]
pseudo-color image of IDCS J1426.5+3508, with the SZ contours overplotted. The optical and infrared data are from the NOAO Deep,
Wide–Field Survey (NDWFS; Jannuzi and Dey 1999) and SDWFS, respectively. Lower panel: HST F814W+F160W pseudo-color zoom–in
of IDCS J1426.5+3508. The SZ contours (green) from the present work and X-ray contours (yellow) from S12, corresponding to 0.131,
0.077 and 0.044 counts per 2′′ × 2′′ pixel in 8.3 ks in the 0.5-2 KeV band, are overplotted. Two sources are indicated by hash marks. The
northern source is an X-ray luminous QSO that is also a cluster member; the southern source is a radio-bright AGN, the emission from
which was removed from the SZA map. Both are discussed further in the text. In all panels North is up, East is left, and a scale bar is
given.
4. 4 Brodwin et al.
profile P (r) is determined by fitting a model profile to and the total cluster mass. By convention, both the total
the SZA data. We adopt the generalized Navarro et al. cluster mass and the integrated y-parameter are reported
(1997) model proposed by Nagai et al. (2007): within a radius corresponding to a fixed overdensity
∆ = 500 relative to the critical density of the Universe
P0 at the redshift of the cluster. The integrated quantities
P (r) = , (2)
xγ (1 + xα )(β−γ)/α are determined by finding the overdensity radius r500
3
(equivalent to the mass, since M∆ = (4πr∆ /3)∆ρc (z))
where x = r/rs . We fix the power law exponents (α, β, γ) and integrated y-parameter Y500 that are mutually con-
to the “universal” values reported by Arnaud et al.
sistent with the Andersson et al. (2011) M500 –Y500 scal-
(2010), and leave P0 and rs free to vary14 . ing relation. We choose this relation since the clus-
One important source of systematic errors in SZ cluster ters with which it is measured have the highest mean
measurements is radio point sources. These synchrotron
redshift. The self-consistent values of r500 and Y500
sources are often variable, are known to be correlated are determined iteratively at each step in the MCMC,
with clusters, and can fill in the SZ decrement at low fre- and the scaling relation parameters are sampled at each
quencies (see, e.g., Carlstrom et al. 2002). Wide angu-
step using their reported means and variances. Using
lar scale surveys such as the SPT survey generally mask this method, we find that M500,c = (2.6 ± 0.7) × 1014
regions where bright point sources are detected, which M⊙ , where the error is statistical in nature. Assuming
changes the survey selection function but can be ac-
the Duffy et al. (2008) concentration relation, this cor-
counted for using simulations (Vanderlinde et al. 2010).
However, for targeted SZ follow-up of sources selected in responds to M200,c = (4.1 ± 1.1) × 1014 M⊙ . This mass
other bands, point source fluxes must be measured and agrees well with the X-ray mass of M200,c ≃ 5.6 × 1014
removed in order to accurately estimate the cluster mass. M⊙ , for which the error is at least 40%.
Due to the temporal variability of these sources, the point A significant uncertainty, inherent to both SZ and X-
source fluxes ideally should be determined concurrently ray measurements of the masses of high redshift clus-
with the SZ measurement. The SZA uses its longer ters, is due to the fact that no published mass-observable
outrigger baselines to perform such simultaneous point scaling relation has been estimated using a sample con-
source measurements. For spatially compact sources, the taining clusters at redshifts significantly greater than
emission measured on the outrigger baselines (smaller unity. While Andersson et al. (2011) found no com-
angular scales) can be assumed to be representative of pelling evidence for redshift evolution in the M500 –Y500
the emission measured on the short SZ-sensitive base- scaling relation out to z ∼ 1, their sample consisted
lines (larger angular scales), and can thereby be removed of lower-redshift and higher-mass objects whose scaling
from the SZ signal (see, e.g., Muchovej et al. 2007). properties may be systematically different from those of
Two such point sources were discussed in S12 and are IDCS J1426.5+3508.
indicated by hash marks in Figure 1. The northern To enable the SZ mass of IDCS J1426.5+3508 to be
source is an X-ray bright QSO that is also a spectro- easily calculated with future scaling relations, we also re-
scopically confirmed member of IDCS J1426.5+3508. As port the spherically-averaged dimensionless Comptoniza-
described in S12, the contribution to the cluster’s X-ray tion, Ysph,500 = (7.9 ± 3.2) × 10−12 . This corresponds to
flux from this QSO had to be removed to obtain a reliable a gas mass at r500 of Mgas = (2.9 ± 1.2) × 1013 M⊙ for a
cluster mass. This QSO is not detected in the radio, how- constant temperature of 5 keV. This temperature is con-
ever, with a formal 31 GHz flux density of −0.04 ± 0.31 sistent with the X-ray measurement (S12); for a cooler 4
mJy, and therefore it has no impact on the measured keV cluster the inferred gas mass would increase by 25%.
cluster mass. A second point source, bright enough in the To assess the SZ detection significance, we fit a clus-
radio to fill in the SZ decrement of IDCS J1426.5+3508, ter model to the visibility data and compare to a null
was identified near the cluster center at 14h 26m 32.1, s model. Our model consists of an elliptical Gaussian SZ
35◦ 08′ 15. 2, indicated by the southern hash mark in Fig-
′′ decrement located at the X-ray centroid along with the
ure 1. This source corresponds to a ∼ 95 mJy source nearby radio point source, and our null model consists
identified at 1.4 GHz in the NVSS (Condon et al. 1998) only of the point source. We find a ∆χ2 of 37.65 between
and FIRST (Becker et al. 1995) catalogs. The lower– the model and null model fits. Since the (fixed-position)
frequency radio survey data indicate that this source is elliptical Gaussian adds four degrees of freedom, this ∆χ2
unresolved at the angular scales to which the SZA is corresponds to a detection significance of 5.3 σ, or a false
sensitive, allowing it to be modeled as a point source detection probability of 1.32 × 10−7. Because the SZ sig-
and constrained using the long baseline data. The flux nal was sought only at the position of the X-ray emis-
density of this source is left as a free parameter in the sion, this detection is very secure. In contrast, a false
cluster model fit, and is found to be 5.3 ± 0.3 mJy. The 5.3 sigma detection is far more plausible in a wide–field
resulting spectral index of −0.93 ± 0.02 is consistent with survey like SPT because there are of order 106 indepen-
synchrotron radiation. dent pixels in which such a deviation can arise by chance.
A Markov Chain Monte Carlo (MCMC) fit is used to We therefore consider the pointed, follow-up detection of
jointly constrain P0 , rs , and the flux densities of the two IDCS J1426.5+3508 to be robust.
point sources in our fiducial cosmology. The results of If the cluster position is not fixed to the X-ray cen-
this fit are used to compute the integrated y-parameter troid, the best–fit centroid of the SZ signal is 14h 26m34.0,s
35◦ 08′ 02. 6, which is slightly offset (≈ 32′′ and 25′′ ) from
′′
14 Arnaud et al. (2010) suggest other power law exponents ap-
the X-ray and BCG positions, respectively. As the uncer-
propriate for clusters with a known morphology, but Marrone et al. tainty in the SZ centroid is ≈ 35′′ , this offset is not sta-
(2011) find that these alternative choices make a 5% difference
in the estimate of Y500 . tistically significant. Absent the X-ray positional prior,
5. IDCS J1426.5+3508: SZ Measurement of a Massive IR-selected Cluster at z = 1.75 5
the significance of the SZ detection is almost identical
(5.2 σ). 1016
4. PROBABILITY OF EXISTENCE IN A ΛCDM UNIVERSE Fu
ll S
ky
SP
While not as massive as the z ∼ 1 SPT clusters, TP
rev
IDCS J1426.5+3508, by virtue of its exceptional redshift SP
T(
iew
(25
17 00
and substantial mass, is arguably one of the more ex- 8d
eg 2
de
g2
)
M200,m [MO]
treme systems discovered to date. It is therefore inter- )
•
esting to calculate the probability of discovering it in the
1015
IDCS in a standard ΛCDM Universe. IDC
We use the exclusion curve formalism presented in S
Mortonson et al. (2011, hereafter M11), which tests
whether a single cluster is rare enough to falsify ΛCDM J1426.5
and quintessence at a given significance level, account-
ing for both sample and parameter variance. The M11
formalism uses cluster masses measured within a sphere
defined by an overdensity 200 times the mean, rather 1014
than critical, density of the Universe. In this convention,
0.0 0.5 1.0 1.5 2.0
adopting the Duffy et al. (2008) mass–concentration re- Redshift
lation, IDCS J1426.5+3508 has a mass of M200,m =
(4.3 ± 1.1) × 1014 M⊙ . Figure 2. M11-style plot showing the mass and redshift of
The M11 formalism requires that observed cluster IDCS J1426.5+3508 (large red circle), along with other z > 1
masses be corrected for Eddington bias caused by the ISCS clusters (Brodwin et al. 2011; Jee et al. 2011, small red cir-
steep slope of the cluster mass function at this mass cles) and SPT clusters (Williamson et al. 2011, small blue circles;
Brodwin et al. 2010, small cyan circle). The solid red curve is
scale and redshift. We follow the prescription given in the 95% exclusion curve for the IDCS area. The cyan, blue and
Appendix A of M11: black curves are the exclusion curves for the currently published
full depth SPT survey (178 deg2 , Vanderlinde et al. 2010), the
1 2 2500 deg2 SPT preview survey of Williamson et al. (2011) and
ln M = ln Mobs + γσln M , (3) the full sky, respectively. The square symbol represents clus-
2 ter SPT-CL J0102-4915, first reported as ACT-CL J0102-4915
where M is the expected value for the true mass given the (Menanteau et al. 2010). We plot this cluster at the spectroscopic
redshift of z = 0.870 reported in Menanteau et al. (2012). All
observed mass, γ is the local slope of the mass function, clusters are color-coded to the appropriate exclusion curve.
and σ is the uncertainty associated with the observations.
Here we use the fitting function for γ provided in M11, of the SPT survey does not contain a single cluster
which yields γ = −5.8. We thus derive that the expected comparable to IDCS J1426.5+3508 in mass and redshift
value for this bias-corrected mass is M200,m = (3.6 ± (Vanderlinde et al. 2010), which suggests that the true
0.9) × 1014 M⊙ . abundance of such clusters is far lower than our dis-
In Figure 2 we plot the appropriately bias-corrected covery would indicate. Neither the Atacama Cosmol-
mass for IDCS J1426.5+3508 along with 95% con- ogy Telescope (ACT) project nor the Planck project sur-
fidence exclusion curves using the M11 prescription. veys are sensitive enough to detect IDCS J1426.5+3508
For comparison we include rare, massive clusters from (Marriage et al. 2011; Planck Collaboration et al. 2011).
the SPT survey (Williamson et al. 2011; Brodwin et al. If we consider IDCS J1426.5+3508 to have been drawn
2010) and other massive z > 1 clusters from the ISCS from an area of at least ∼ 178 deg2 (shown as the cyan
for which weak lensing or X-ray masses are available curve in Fig. 2) rather than the IDCS volume, then the
(Brodwin et al. 2011; Jee et al. 2011). All masses are cluster is no longer in contradiction with ΛCDM; we were
deboosted in accordance with the M11 prescription. simply somewhat lucky to detect it in the comparatively
The lowest curve in the figure corresponds to the 95% tiny (8.82 deg2 ) IDCS area.
exclusion curve for clusters within the 8.82 deg2 IDCS
area. The central value of the deboosted SZ mass is 5. EVOLUTION TO THE PRESENT DAY
above the curve, formally falsifying ΛCDM at the 95% Although the mere existence of IDCS J1426.5+3508
level. We note, however, that the statistical error bar may not have significant cosmological implications, it
overlaps the exclusion curve. Furthermore, uncertainties is nevertheless among the rarest, most extreme clusters
in the scaling relation could easily lower the mass below ever discovered. As such, it is interesting to understand
the exclusion curve. its nature in the context of the growth of the largest
Rather than asking whether such a cluster should have structures.
been detected in the IDCS, perhaps a fairer question Using the Tinker et al. (2008) mass function, we
is to ask whether such a cluster should have been de- first identify the space density of clusters at z =
tected in the full area of sky covered by all cluster 1.75 that have masses greater to or equal to that of
surveys capable of detecting such a cluster. Numer- IDCS J1426.5+3508. At each redshift we then asso-
ous X-ray surveys of varying areas and depths could ciate the clusters with that space density with its de-
have detected IDCS J1426.5+3508, but for simplicity scendents. In Figure 3 we plot the mass evolution of
we consider the SPT survey, which has the sensitiv- IDCS J1426.5+3508 (large red circle) from z = 1.75 to
ity to detect clusters like IDCS J1426.5+3508, even at the present day (thick black line). For comparison we
z = 1.75 (Vanderlinde et al. 2010). The first 178 deg2 also plot a representative selection of the most extreme
6. 6 Brodwin et al.
clusters found to date at all redshifts. This abundance– massive collapsed structures evolving in the Universe.
matching calculation is designed to predict the mean ex- Although it was discovered in a small (≈ 9 deg2 )
pected growth of IDCS J1426.5+3508. We note that infrared-selected cluster survey, the odds of finding such
there are intrinsic variations in accretion histories due a rare, massive cluster were quite low, 0.8% (0.2%) us-
to the stochastic nature of mergers (e.g., Wechsler et al. ing the Holz and Perlmutter (2010) formalism with the
2002), but consider a full treatment beyond the scope of deboosted (measured) mass. Finding the precursors of
the present work. IDCS J1426.5+3508 at even earlier times will require
As demonstrated in this figure, IDCS J1426.5+3508 is much larger surveys.
much more than just another massive, very high redshift In this section we examine why the current genera-
cluster. It is an evolutionary precursor to the most mas- tion of SZ surveys, despite covering areas ranging from
sive known clusters at all redshifts. Indeed, its descen- 102 –104 deg2 , have not yet seen a cluster as extreme as
dent population consists of the most massive virialized IDCS J1426.5+3508 at z > 1.5. We also discuss the po-
objects ever discovered. tential of the next generation of SZ surveys to discover
There are no other confirmed clusters at z > 1.75 its evolutionary precursors.
with masses greater than 1014 M⊙ . Between 1.5 < z <
1.75 only one cluster, XDCP J0044.0-2033 at z = 1.58 6.1. Current SZ surveys
(Santos et al. 2011; Fassbender et al. 2011), is compara-
ble to IDCS J1426.5+3508, though it is somewhat less The detectability of a cluster like IDCS J1426.5+3508
massive and below the growth trend. in an SZ cluster survey depends on three factors. The
The most massive z > 1 X-ray selected cluster, survey must have sufficient mass sensitivity at high red-
XMMU J2235.3-2557 at z = 1.39 (Mullis et al. 2005; shift, it must cover sufficient area so that the expectation
Rosati et al. 2009), falls along the evolutionary path of value of the number of clusters is greater than unity, and
IDCS J1426.5+3508, as does the most massive z > 1 the clusters in question must not contain bright radio
cluster in the SPT survey, SPT-CL 2106-5844 at z = 1.13 point sources nor have any along the line of sight.
(Foley et al. 2011; Williamson et al. 2011). Similarly, In terms of sensitivity, only the SPT survey is cur-
the only z ∼ 1 Planck cluster reported to date, PLCK rently capable of detecting IDCS J1426.5+3508 at this
G266.6-27.3 at z = 0.94 is also consistent. high redshift. Vanderlinde et al. (2010) report a for-
SPT-CL J0102-4915, first reported as ACT-CL J0102- mal 50% completeness of M200,m ≈ 3.5 × 1014 M⊙ at
4915 from the ACT survey (Menanteau et al. 2010; z = 1.5, and this improves to 90% at z = 1.75. That
Marriage et al. 2011), is among the most significant de- mass limit is below both the measured and deboosted
tections overall in both of these SZ surveys. Masses mass of IDCS J1426.5+3508. So the SPT should nom-
of this cluster from the two SZ surveys are plotted inally have detected such a cluster were it present at
as the square symbols at the spectroscopic redshift of z = 1.75 in the single-band analysis of their first 178 deg2
z = 0.870 (Menanteau et al. 2012). The lower SPT (Vanderlinde et al. 2010). However, since the SPT com-
mass is measured from the SZ decrement, whereas the pleteness limit at high redshift is uncertain at the 30%
higher ACT mass (slightly offset in redshift for clar- level in mass (Vanderlinde et al. 2010), the non-detection
ity) is combined from several methods. The masses of a single high–redshift cluster like IDCS J1426.5+3508
are consistent within the errors. IDCS J1426.5+3508 is unremarkable.
is consistent with growing into a cluster like this as A more interesting question, related to the second cri-
well. RX J1347-1145 (Allen et al. 2002; Lu et al. 2010) terion and to the rarity analysis of §4, is that of how
is the most luminous X-ray cluster in the sky, though many such clusters are actually expected in the cur-
it is not quite massive enough to be considered a de- rent SPT area? According to the Holz and Perlmutter
scendent of IDCS J1426.5+3508. In the local Universe (2010) formulation, we expect only 0.2 such clusters
the Coma cluster represents the kind of extreme cluster in 178 deg2 , and therefore none should have been
IDCS J1426.5+3508 will evolve into. found. In the complete, full-depth 2500 deg2 SPT sur-
Holz and Perlmutter (2010) recently predicted the vey, Holz and Perlmutter (2010) predict the presence of
properties of the single most massive cluster that can 2.4 such clusters, though shot noise will play a role in
form in a ΛCDM Universe with Gaussian initial con- whether any are found.
ditions and where the growth of structure follows the Finally, as discussed in §3.2, IDCS J1426.5+3508 has
predictions of general relativity. They predict this clus- a radio–bright AGN at z = 1.535 along the line-of-sight,
ter should be found at z = 0.22 and have a mass of indicated by the southern hash marks in Figure 1. At
M200,m = 3.8 × 1015 M⊙ . Their 68% contour in pre- a redshift separation of ∆z > 0.2, it is not physically
dicted mass and redshift is shown as a light blue contour associated with the cluster. Its radio emission was con-
and labeled HP10 in the figure. IDCS J1426.5+3508 is strained using the long SZA baselines, which are insen-
completely consistent with being an evolutionary precur- sitive to the arcminute angular scale SZ decrement. If
sor to the most massive halo predicted to exist in the the measured 1.4 to 31 GHz spectral index of this source
observable Universe. (−0.93) is valid to 150 GHz, the AGN flux would be 1.2
mJy at this frequency, well below the 5 mJy threshold
6. DISCUSSION for masking individual point sources in the SPT survey.
Given its extreme mass it is not surprising that However, it would partially fill in the ∼ 14 mJy SZ decre-
IDCS J1426.5+3508 was detected in shallow (5 ks) Chan- ment at 150 GHz, reducing the SPT detection signifi-
dra images (S12), despite its high redshift. The ro- cance and biasing the mass estimate low by ∼ 10 − 15%.
bust, high-significance SZA detection reported herein It is possible that the AGN content of clusters at the
confirms that IDCS J1426.5+3508 is one of the most highest redshifts may be substantially larger than at in-
7. IDCS J1426.5+3508: SZ Measurement of a Massive IR-selected Cluster at z = 1.75 7
1016
Coma
HP10
SPT-CL/ACT-CL
J0102-4915
RX J1347-1145
PLCK G266.6-27.3
M200,m [MO]
•
XMMU
15 J2235.3-2557
10
SPT SPT-CL IDCS
(Willamson et al. 2011) J2106-5844 J1426.5+3508
XDCP
J0044.0-2033
1014
0.0 0.5 1.0 1.5 2.0
Redshift
Figure 3. Predicted mass growth of IDCS J1426.5+3508 vs. redshift based on abundance matching. IDCS J1426.5+3508 is the large
red circle and the predicted growth in its mass is shown as a thick black line. The 1 σ errors, stemming from the mass measurement
errors, are shown as the shaded region. An assortment of the rarest, most massive clusters found at all redshift is shown for comparison
and discussed in the text. SPT-CL J0102-4915 was first reported as ACT-CL J0102-4915 by Menanteau et al. (2010) and Marriage et al.
(2011). The independent mass measurements from both surveys are plotted as the square symbols for this cluster at the spectroscopic
redshift (z = 0.8701) reported in Menanteau et al. (2012). IDCS J1426.5+3508 is consistent with being a member of the most extreme
population of virialized structures in the Universe.
termediate (z < 1) redshifts. Indeed, Galametz et al. simultaneously identify and remove contamination from
(2009) find evidence for a strong increase in the inci- such (generally variable) sources, as in this work, and
dence of AGN in clusters with redshift from 0.2 < z < thus recover accurate cluster masses.
1.4, particularly for X-ray and IR-selected AGN. The
evidence for rapid number density evolution in radio- 6.2. Next–Generation SZ surveys
selected AGN is not as conclusive. In some surveys (e.g., Several next–generation SZ experiments designed
Galametz et al. 2009) it increases as quickly in clusters as for CMB polarization measurements, such as SPTpol
in the field, whereas others (e.g., Gralla et al. 2011) find (Bleem et al. 2012) and ACTpol (Niemack et al. 2010),
it is roughly constant. One major advantage of CARMA are currently being deployed. These experiments will
for targeted SZ observations of clusters is the ability to possess typical SZ mass sensitivities a factor of sev-
8. 8 Brodwin et al.
eral lower than present surveys. Here we calculate by far the most distant cluster with an SZ detection to
the expected yield of high–redshift clusters similar to date. Using the Andersson et al. (2011) M500 –Y500 scal-
IDCS J1426.5+3508 for a canonical 500 deg2 next– ing relation, we find M200,m = (4.3 ± 1.1) × 1014 M⊙ , in
generation survey with constant M200,m completeness agreement with the X-ray mass reported in S12.
limits of 1.2 × 1014 M⊙ and 1.5 × 1014 M⊙ at the 50% The chance of finding IDCS J1426.5+3508 in the ∼
and 90% levels, respectively. 9 deg2 IDCS was 1%, which, taken at face value,
The same methodology that explains the lack of a marginally rules out ΛCDM. Within the much larger to-
cluster like IDCS J1426.5+3508 in the current SPT tal area probed by other SZ and X-ray surveys, its exis-
survey area predicts that a significant number of very tence is not unexpected.
high redshift clusters, somewhat less massive than In a ΛCDM cosmology, with the growth of structure
IDCS J1426.5+3508, will be found with the polarization as predicted by general relativity, IDCS J1426.5+3508
experiments. Figure 4 shows the expected cumulative will grow to a mass of M200,m ≈ 4.7 × 1015 M⊙ by the
yield, based on the Holz and Perlmutter (2010) formula- present day. It therefore shares an evolutionary path
tion, at the two mass limits given above, accounting for with the most massive known clusters at every redshift.
the expected completenesses. Along with several of the rarest, high-redshift clusters
The combination of area and depth of the next genera- currently known, IDCS J1426.5+3508 is consistent with
tion SZ surveys will allow them to identify a large statis- evolving into the single most massive cluster expected to
tical sample of massive, hot clusters at 1.5 < z < 2.0. exist in the observable Universe.
As such they provide a natural extension of the in-
frared surveys, which have characterized galaxy clusters
to z = 1.5. A 100 deg2 region that will be covered by Support for CARMA construction was derived from
both SPTpol and ACTpol will also contain Spitzer in- the states of California, Illinois, and Maryland, the
frared data, from an ongoing Spitzer Exploration Class James S. McDonnell Foundation, the Gordon and Betty
program (PID 80096, PI Stanford). This will allow opti- Moore Foundation, the Kenneth T. and Eileen L. Norris
mal high-redshift cluster detection and study at both IR Foundation, the University of Chicago, the Associates
and mm wavelengths, the only two cluster probes that of the California Institute of Technology, and the Na-
are nearly redshift-independent at 1 < z < 2. tional Science Foundation. Ongoing CARMA develop-
Despite the wealth of new, high redshift clusters to ment and operations are supported by the National Sci-
be found by the next-generation SZ surveys, there are ence Foundation under a cooperative agreement, and by
only even odds (p ∼ 0.5) of finding a z = 2 precursor to the CARMA partner universities. The work at Chicago
IDCS J1426.5+3508. Unless, of course, we are fortunate is supported by NSF grant AST-0838187 and PHY-
once again. 0114422.
This work is based in part on observations made with
the Spitzer Space Telescope, which is operated by the
150 Jet Propulsion Laboratory, California Institute of Tech-
M200,m > 1.2 x 1014 MO
•
nology under a contract with NASA. Support for this
M200,m > 1.5 x 1014 MO
work was provided by NASA through an award issued by
•
JPL/Caltech. This work is based in part on observations
obtained with the Chandra X-ray Observatory (CXO),
100
under contract SV4-74018, A31 with the Smithsonian
Astrophysical Observatory which operates the CXO for
Number (>z)
NASA. Support for this research was provided by NASA
grant G09-0150A. Support for HST programs 11663 and
12203 were provided by NASA through a grant from the
Space Telescope Science Institute, which is operated by
50 the Association of Universities for Research in Astron-
omy, Inc., under NASA contract NAS 5-26555. This
work is based in part on data obtained at the W. M. Keck
Observatory, which is operated as a scientific partnership
among the California Institute of Technology, the Uni-
0 versity of California and the National Aeronautics and
1.5 1.6 1.7 1.8 1.9 2.0 Space Administration. The Observatory was made pos-
Redshift sible by the generous financial support of the W. M. Keck
Foundation. This work makes use of image data from
Figure 4. Predicted cumulative counts of massive 1.5 < z < the NOAO Deep Wide–Field Survey (NDWFS) as dis-
2 clusters at the 50% (M200,m = 1.20 × 1014 M⊙ ) and 90% tributed by the NOAO Science Archive. NOAO is op-
(M200,m = 1.5 × 1014 M⊙ ) completeness limits of a representa- erated by the Association of Universities for Research
tive 500 deg2 next–generation SZ survey. The curves account for in Astronomy (AURA), Inc., under a cooperative agree-
losses due to incompleteness. The arrow indicates the redshift of ment with the National Science Foundation.
IDCS J1426.5+3508.
We thank the anonymous referee for suggestions which
improved the manuscript, Bradford Benson for help-
7. CONCLUSIONS ful discussions, F. Will High and Keith Vanderlinde
We have presented a robust 5.3 σ SZ detection of the for providing published SPT masses in a digital form,
infrared-selected cluster IDCS J1426.5+3508 at z = 1.75, Matt Ashby for creating the IRAC catalogs for SDWFS,
9. IDCS J1426.5+3508: SZ Measurement of a Massive IR-selected Cluster at z = 1.75 9
Michael Brown for combining the NDWFS with SDWFS Gonzalez, A. H., et al. 2012, ApJ, submitted
catalogs, Alexey Vikhlinin for advice on the analysis of Gralla, M. B., Gladders, M. D., Yee, H. K. C., and Barrientos,
the Chandra data, and Daniel Holz for providing his L. F. 2011, ApJ, 734, 103
Holz, D. E. and Perlmutter, S. 2010, arXiv:1004.5349
predictions in an electronic format. This paper would Hotchkiss, S. 2011, J. Cosmology Astropart. Phys., 7, 4
not have been possible without the efforts of the sup- Hoyle, B., Jimenez, R., and Verde, L. 2011, Phys. Rev. D,
port staffs of CARMA, the Keck Observatory, Spitzer 83(10), 103502
Space Telescope, Hubble Space Telescope, and Chandra Jannuzi, B. T. and Dey, A. 1999, in ASP Conf. Ser. 191 —
X-ray Observatory. Support for MB was provided by Photometric Redshifts and the Detection of High Redshift
Galaxies, p. 111
the W. M. Keck Foundation. AHG acknowledges sup- Jee, M. J., et al. 2011, ApJ, 737, 59
port from the National Science Foundation through grant Komatsu, E., et al. 2011, ApJS, 192, 18
AST-0708490. The work by SAS at LLNL was performed Lu, T., et al. 2010, MNRAS, 403, 1787
under the auspices of the U. S. Department of Energy Marriage, T. A., et al. 2011, ApJ, 737, 61
Marrone, D. P., et al. 2011, ApJ, submitted (arXiv:1107.5115)
under Contract No. W-7405-ENG-48. Menanteau, F., et al. 2010, ApJ, 723, 1523
Menanteau, F., et al. 2012, ApJ, in press (arXiv:1109.0953)
REFERENCES Mortonson, M. J., Hu, W., and Huterer, D. 2011, Phys. Rev. D,
83(2)
Muchovej, S., et al. 2007, ApJ, 663, 708
Mullis, C. R., Rosati, P., Lamer, G., B¨hringer, H., Schwope, A.,
o
Allen, S. W., Evrard, A. E., and Mantz, A. B. 2011, ARA&A,
Schuecker, P., and Fassbender, R. 2005, ApJ, 623, L85
submitted (arXiv:1103.4829)
Allen, S. W., Schmidt, R. W., and Fabian, A. C. 2002, MNRAS, Murray, S. S., et al. 2005, ApJS, 161, 1
335, 256 Muzzin, A., Wilson, G., Lacy, M., Yee, H. K. C., and Stanford,
Andersson, K., et al. 2011, ApJ, 738, 48 S. A. 2008, ApJ, 686, 966
Arnaud, M., Pratt, G. W., Piffaretti, R., B¨hringer, H., Croston,
o Nagai, D., Kravtsov, A. V., and Vikhlinin, A. 2007, ApJ, 668, 1
J. H., and Pointecouteau, E. 2010, A&A, 517, A92 Navarro, J. F., Frenk, C. S., and White, S. D. M. 1997, ApJ,
Ashby, M. L. N., et al. 2009, ApJ, 701, 428 490, 493
Becker, R. H., White, R. L., and Helfand, D. J. 1995, ApJ, 450, Niemack, M. D., et al. 2010, in Society of Photo-Optical
559 Instrumentation Engineers (SPIE) Conference Series, Vol.
Bleem, L., et al. 2012, Journal of Low Temperature Physics pp 7741 of Society of Photo-Optical Instrumentation Engineers
1–6, 10.1007/s10909-012-0505-y (SPIE) Conference Series
Brodwin, M., et al. 2006, ApJ, 651, 791 Paranjape, A., Gordon, C., and Hotchkiss, S. 2011,
Brodwin, M., et al. 2010, ApJ, 721, 90 Phys. Rev. D, 84(2), 023517
Brodwin, M., et al. 2011, ApJ, 732, 33 Planck Collaboration, Ade, et al. 2011, A&A, in press
Carlstrom, J. E., et al. 2011, PASP, 123, 568 (arXiv:1101.2024)
Carlstrom, J. E., Holder, G. P., and Reese, E. D. 2002, ARA&A, Rosati, P., et al. 2009, A&A, 508, 583
40, 643 Rudy, D. J., Muhleman, D. O., Berge, G. L., Jakosky, B. M., and
Cay´n, L., Gordon, C., and Silk, J. 2011, MNRAS, 415, 849
o Christensen, P. R. 1987, Icarus, 71, 159
Condon, J. J., Cotton, W. D., Greisen, E. W., Yin, Q. F., Perley, Santos, J. S., et al. 2011, A&A, 531, L15
R. A., Taylor, G. B., and Broderick, J. J. 1998, AJ, 115, 1693 Sault, R. J., Teuben, P. J., and Wright, M. C. H. 1995, in
Culverhouse, T. L., et al. 2010, ApJ, 723, L78 R. A. Shaw, H. E. Payne, & J. J. E. Hayes (ed.), Astronomical
Dalal, N., Dor´, O., Huterer, D., and Shirokov, A. 2008,
e Data Analysis Software and Systems IV, Vol. 77 of
Phys. Rev. D, 77, 123514 Astronomical Society of the Pacific Conference Series, p. 433
Duffy, A. R., Schaye, J., Kay, S. T., and Dalla Vecchia, C. 2008, Stanford, S. A., et al. 2012, ApJ, submitted
MNRAS, 390, L64 Stanford, S. A., et al. 2005, ApJ, 634, L129
Eisenhardt, P. R., et al. 2004, ApJS, 154, 48 Tinker, J., Kravtsov, A. V., Klypin, A., Abazajian, K., Warren,
Eisenhardt, P. R. M., et al. 2008, ApJ, 684, 905 M., Yepes, G., Gottl¨ber, S., and Holz, D. E. 2008, ApJ, 688,
o
Elston, R. J., et al. 2006, ApJ, 639, 816 709
Enqvist, K., Hotchkiss, S., and Taanila, O. 2011, J. Cosmology Vanderlinde, K., et al. 2010, ApJ 722, 1180
Astropart. Phys., 4, 17 Vikhlinin, A., et al. 2009, ApJ, 692, 1033
Fassbender, R., et al. 2011, New Journal of Physics, in press Wechsler, R. H., Bullock, J. S., Primack, J. R., Kravtsov, A. V.,
(arXiv:1111.0009) and Dekel, A. 2002, ApJ, 568, 52
Foley, R. J., et al. 2011, ApJ, 731, 86 Williamson, R., et al. 2011, ApJ, 738, 139
Galametz, A., et al. 2009, ApJ, 694, 1309