Observações obtidas nos Observatórios de La Silla e Paranal no Chile demonstraram pela primeira vez que existe uma ligação entre uma explosão de raios gama de longa duração e uma explosão de supernova de brilho incomum. Os resultados mostram que a supernova não teve origem em decaimento radioativo, como se esperava, mas sim em campos magnéticos muito fortes decaindo em torno de um objeto exótico conhecido como magnetar. Os resultados serão publicados em 9 de julho de 2015 na revista Nature.
As explosões de raios gama constituem um dos eventos associados às maiores explosões que ocorreram desde o Big Bang. São detectadas por telescópios em órbita sensíveis a este tipo de radiação altamente energética, a qual não consegue penetrar a atmosfera terrestre, e são igualmente observadas a maiores comprimentos de onda por outros telescópios, situados tanto no espaço como no solo.
As explosões de raios gama duram tipicamente alguns segundos, mas em casos muito raros podem ocorrer durante horas. Uma destas explosões de longa duração foi captada pelo satélite Swift a 9 de dezembro de 2011 e chamada GRB 111209A. Foi simultaneamente uma das mais longas e mais brilhantes explosões de raios gama jáobservada.
Sdss1133 an unsually_perssitent_transient_in_a_nearby_dwarf_galaxySérgio Sacani
This document summarizes observations of SDSS1133, an unusual transient object offset from the center of a nearby dwarf galaxy. SDSS1133 has been detected in observations spanning 63 years, and exhibits broad emission lines and strong variability. While initially classified as a supernova due to its non-detection in 2005, more recent observations over the past decade show it has rebrightened over a magnitude and displays properties consistent with both an active galactic nucleus and luminous blue variable star eruptions. Its nature remains ambiguous between an extreme example of pre-supernova mass loss or a potential candidate for a recoiling supermassive black hole.
This paper presents a study of the extended X-ray emission in the Seyfert galaxy NGC 4151 using deep Chandra observations. Key findings include:
1) Emission line maps show strong OVII, OVIII, and NeIX line emission extending along the northeast-southwest direction, consistent with an ionization cone.
2) Spectral analysis finds the extended emission is well described by photoionized plasma models, supporting a dominant role for nuclear photoionization.
3) Faint extended emission is also seen perpendicular to the ionization cone, indicating some leakage of nuclear ionizing radiation through warm absorbers rather than being blocked by an obscuring torus.
Grb 130606a as_a_probe_of_the_intergalactic_medium_and_the_interstelar_medium...Sérgio Sacani
This document summarizes observations of the gamma-ray burst GRB 130606A at a redshift of z=5.913 using spectroscopy from the MMT and Gemini telescopes. The high quality spectra exhibit a smooth near-infrared continuum that is sharply cut off by Lyman-alpha absorption at z=5.91, with some flux transmitted through the Lyman-alpha forest at lower redshifts. Metal absorption lines in the host galaxy are used to constrain its metallicity between -1.7 and -0.5 solar. Transmission in the Lyman-alpha forest is found to evolve consistently with previous quasar observations. An extended region at z=5.77 shows no Lyman-alpha transmission,
This document presents observations from the VLT X-shooter instrument of two quasars, SDSS J1106+1939 and SDSS J1512+1119. For SDSS J1106+1939, a broad absorption line (BAL) outflow is detected with a kinetic luminosity of at least 10^46 erg/s, which is 5% of the quasar's bolometric luminosity. This outflow has a velocity of ~8000 km/s and is located ~300 pc from the quasar. For SDSS J1512+1119, two separate outflows are detected using the same technique, with distances ranging from 100-2000 pc from the central source. The distances of the outflows
The document summarizes observations of periodic increases in luminosity from a young protostar called L54361. Key points:
1) L54361's luminosity increases by a factor of 10 roughly every 25.34 days, as determined from 81 observations over 7 years.
2) The luminosity increases rapidly over a few days and then decays more slowly over the following few weeks, indicating periodic pulsed accretion.
3) Near-infrared imaging resolved scattered light structures around L54361 that vary similarly, suggesting the luminosity pulses illuminate outflow cavities.
This document summarizes the results of a 180 ks Chandra-LETGS observation of Mrk 509 as part of a larger multi-wavelength campaign. The observation detected several absorption features in the X-ray spectrum originating from an ionized absorber, including ions with three distinct ionization degrees. The lowest ionized component is slightly redshifted and not in pressure equilibrium with the others, likely belonging to the host galaxy's interstellar medium. The other two components are outflowing at velocities of around -200 and -455 km/s. Simultaneous HST-COS observations detected 13 UV kinematic components, and at least three can be associated with the X-ray components, providing evidence that the UV and X-
The central star_of_the_planetary_nebula_ngc_6537Sérgio Sacani
1) HST images of the planetary nebula NGC 6537 fail to detect its central star, placing an upper limit on its magnitude of fainter than 22.4.
2) This limit is used to derive a lower limit for the star's temperature of at least 500,000 K based on Zanstra temperature analysis.
3) The energy balance temperature method, which does not require direct observation of the star, yields a temperature consistent with 500,000 K, as does the ionization state of the nebula.
This study uses deep Chandra observations to examine the X-ray morphology of the circum-nuclear region of NGC 4151 on spatial scales down to 30 pc. Extended soft X-ray emission is detected out to 1.3 kpc from the nucleus, farther than seen in previous studies. The X-ray emission is more absorbed towards the boundaries of the ionization cone and perpendicular to the bicone, suggesting absorption by a torus. The innermost X-ray emission, coincident with H2 emission and dusty spirals, supports X-ray excitation of molecular gas. The extended X-ray emission may be due to hot gas heated by the AGN outflow or photoionized by past AGN activity.
Sdss1133 an unsually_perssitent_transient_in_a_nearby_dwarf_galaxySérgio Sacani
This document summarizes observations of SDSS1133, an unusual transient object offset from the center of a nearby dwarf galaxy. SDSS1133 has been detected in observations spanning 63 years, and exhibits broad emission lines and strong variability. While initially classified as a supernova due to its non-detection in 2005, more recent observations over the past decade show it has rebrightened over a magnitude and displays properties consistent with both an active galactic nucleus and luminous blue variable star eruptions. Its nature remains ambiguous between an extreme example of pre-supernova mass loss or a potential candidate for a recoiling supermassive black hole.
This paper presents a study of the extended X-ray emission in the Seyfert galaxy NGC 4151 using deep Chandra observations. Key findings include:
1) Emission line maps show strong OVII, OVIII, and NeIX line emission extending along the northeast-southwest direction, consistent with an ionization cone.
2) Spectral analysis finds the extended emission is well described by photoionized plasma models, supporting a dominant role for nuclear photoionization.
3) Faint extended emission is also seen perpendicular to the ionization cone, indicating some leakage of nuclear ionizing radiation through warm absorbers rather than being blocked by an obscuring torus.
Grb 130606a as_a_probe_of_the_intergalactic_medium_and_the_interstelar_medium...Sérgio Sacani
This document summarizes observations of the gamma-ray burst GRB 130606A at a redshift of z=5.913 using spectroscopy from the MMT and Gemini telescopes. The high quality spectra exhibit a smooth near-infrared continuum that is sharply cut off by Lyman-alpha absorption at z=5.91, with some flux transmitted through the Lyman-alpha forest at lower redshifts. Metal absorption lines in the host galaxy are used to constrain its metallicity between -1.7 and -0.5 solar. Transmission in the Lyman-alpha forest is found to evolve consistently with previous quasar observations. An extended region at z=5.77 shows no Lyman-alpha transmission,
This document presents observations from the VLT X-shooter instrument of two quasars, SDSS J1106+1939 and SDSS J1512+1119. For SDSS J1106+1939, a broad absorption line (BAL) outflow is detected with a kinetic luminosity of at least 10^46 erg/s, which is 5% of the quasar's bolometric luminosity. This outflow has a velocity of ~8000 km/s and is located ~300 pc from the quasar. For SDSS J1512+1119, two separate outflows are detected using the same technique, with distances ranging from 100-2000 pc from the central source. The distances of the outflows
The document summarizes observations of periodic increases in luminosity from a young protostar called L54361. Key points:
1) L54361's luminosity increases by a factor of 10 roughly every 25.34 days, as determined from 81 observations over 7 years.
2) The luminosity increases rapidly over a few days and then decays more slowly over the following few weeks, indicating periodic pulsed accretion.
3) Near-infrared imaging resolved scattered light structures around L54361 that vary similarly, suggesting the luminosity pulses illuminate outflow cavities.
This document summarizes the results of a 180 ks Chandra-LETGS observation of Mrk 509 as part of a larger multi-wavelength campaign. The observation detected several absorption features in the X-ray spectrum originating from an ionized absorber, including ions with three distinct ionization degrees. The lowest ionized component is slightly redshifted and not in pressure equilibrium with the others, likely belonging to the host galaxy's interstellar medium. The other two components are outflowing at velocities of around -200 and -455 km/s. Simultaneous HST-COS observations detected 13 UV kinematic components, and at least three can be associated with the X-ray components, providing evidence that the UV and X-
The central star_of_the_planetary_nebula_ngc_6537Sérgio Sacani
1) HST images of the planetary nebula NGC 6537 fail to detect its central star, placing an upper limit on its magnitude of fainter than 22.4.
2) This limit is used to derive a lower limit for the star's temperature of at least 500,000 K based on Zanstra temperature analysis.
3) The energy balance temperature method, which does not require direct observation of the star, yields a temperature consistent with 500,000 K, as does the ionization state of the nebula.
This study uses deep Chandra observations to examine the X-ray morphology of the circum-nuclear region of NGC 4151 on spatial scales down to 30 pc. Extended soft X-ray emission is detected out to 1.3 kpc from the nucleus, farther than seen in previous studies. The X-ray emission is more absorbed towards the boundaries of the ionization cone and perpendicular to the bicone, suggesting absorption by a torus. The innermost X-ray emission, coincident with H2 emission and dusty spirals, supports X-ray excitation of molecular gas. The extended X-ray emission may be due to hot gas heated by the AGN outflow or photoionized by past AGN activity.
1. This document describes a multiwavelength campaign on the Seyfert 1 galaxy Mrk 509 using five satellites and two ground-based facilities.
2. The campaign aims to study several open questions about active galactic nuclei (AGN), including the location and physics of outflows from AGN, the nature of continuum emission, the geometry and physical state of the X-ray broad emission line region, and the Fe-K line complex.
3. The observations cover more than five decades in frequency, from 2 μm to 200 keV, and include a simultaneous set of deep XMM-Newton and INTEGRAL observations over seven weeks. This allows the authors to disentangle different components and study time variability
Alma observations of_feed_and_feedback_in_nearby_seyfert_galaxiesSérgio Sacani
The ALMA observations of NGC 1433 reveal a nuclear gaseous spiral structure within the central kpc. This spiral winds up into a pseudo-ring at ~200 pc from the center. Near the nucleus, there is intense high-velocity CO emission up to 200 km/s that is interpreted as an outflow, involving 3.6 million solar masses of molecular gas and a flow rate of ~7 solar masses per year. The outflow could be driven by both the central star formation and AGN through its radio jets. Continuum emission at 0.87 mm is detected only at the very center and likely comes from thermal dust emission from the molecular torus expected in this Seyfert 2 galaxy.
A rapidly spinning_supermassive_black_hole_at_the_centre_of_ngc1365Sérgio Sacani
1) XMM-Newton and NuSTAR observed the galaxy NGC 1365 simultaneously over 130 ks, detecting broadband X-ray emission from 3-79 keV.
2) The observations revealed variable absorption below 10 keV and prominent broad emission features between 5-7 keV and 10-30 keV, indicative of relativistic reflection from an accretion disk near a spinning supermassive black hole.
3) Time-resolved spectral analysis was able to disentangle the variable absorption component from the relativistic reflection component. Absorption-dominated models without reflection could be ruled out statistically and on physical grounds.
Discovery of powerful gamma ray flares from the crab nebulaSérgio Sacani
1) The AGILE satellite detected powerful gamma-ray flares from the Crab Nebula in September 2010 and October 2007 that increased the nebula's unpulsed gamma-ray flux by a factor of 3.
2) The flares originated near the nebula's central pulsar and challenge standard models of nebular emission.
3) Synchrotron emission from shock-accelerated electrons along the pulsar's polar jet can explain the gamma-ray flaring, requiring particle acceleration on timescales of about 1 day.
Rapid formation of large dust grains in the luminous supernova SN 2010jlGOASA
This document summarizes observations of rapid dust formation in the luminous supernova SN 2010jl over multiple epochs from 26 to 868 days past peak brightness. Analysis of emission line profiles shows increasing extinction over time, indicating continuous dust formation. The extinction curve implies the presence of very large (>1 micron) dust grains. Thermal emission models suggest dust temperatures declining from 2300K to 1100K over time, requiring carbonaceous rather than silicate dust. Combined extinction and emission data indicate a dust mass of ~0.0025 solar masses at 868 days, growing rapidly and expected to reach ~0.5 solar masses by 8000 days if production continues. The results provide evidence for very efficient and rapid dust formation in the dense
This document discusses using future full-sky galaxy surveys from space telescopes to probe initial conditions and constrain primordial non-Gaussianity. It proposes launching a space telescope called SPHEREx to conduct a full-sky galaxy spectroscopy survey. This would allow probing the horizon-scale clustering needed to constrain the non-Gaussianity parameter fNL using both the galaxy power spectrum and bispectrum. Current forecasts suggest SPHEREx could achieve an uncertainty of σ(fNL) ~ 0.8 from the power spectrum alone and σ(fNL) ~ 0.2 when also including the bispectrum. However, challenges remain in applying photometric redshift indicators and understanding contributions to the squeezed bispectrum at higher orders.
The document summarizes research from images taken by the New Horizons spacecraft of Charon, Pluto's largest moon. The images reveal Charon has a reddish polar cap at its north pole. Thermal models show the pole experiences long periods of extreme cold temperatures due to Charon's high obliquity and long seasons. The researchers hypothesize that methane and other volatiles escaping from Pluto's atmosphere become cold-trapped at Charon's winter pole, where they are processed by radiation into non-volatile organic compounds that remain on the surface to form the red cap. Spectral and compositional evidence supports this mechanism of seasonal accumulation of photolyzed volatiles to explain Charon's unique polar color
The open cluster_ngc6520_and_the_nearby_dark_molecular_cloud_barnard_86Sérgio Sacani
This document presents optical photometry and CO observations of the open cluster NGC 6520 and nearby dark molecular cloud Barnard 86. Analysis of the optical data finds the cluster radius is 1.0±0.5 arcmin, smaller than previous estimates. The cluster age is estimated to be 150±50 Myr with reddening of EB−V =0.42±0.10. The distance from the Sun is estimated to be 1900±100 pc, larger than previous estimates. CO observations are used to derive basic properties of Barnard 86 under the assumption it lies at the same distance as the cluster.
Two gamma ray bursts from dusty regions with little molecular gasGOASA
This document summarizes spatially-resolved observations of two gamma-ray burst (GRB) host galaxies using the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA detected molecular gas emission and dust continuum emission from the nuclear regions of both hosts. However, for one host (GRB 020819B), the GRB explosion site showed dust continuum emission but no molecular gas detection. This suggests the GRB occurred in a dust-rich region with a shortage of molecular gas, unlike typical star-forming regions. The molecular gas-to-dust ratio at the GRB site was much lower than in the host's nuclear region and the Milky Way, indicating the environment where GRBs occur
Identification of the central compact object in the young supernova remnant 1...Sérgio Sacani
Oxygen-rich young supernova remnants1
are valuable objects
for probing the outcome of nucleosynthetic processes in massive
stars, as well as the physics of supernova explosions.
Observed within a few thousand years after the supernova
explosion2
, these systems contain fast-moving oxygen-rich and
hydrogen-poor filaments visible at optical wavelengths: fragments
of the progenitor’s interior expelled at a few thousand
kilometres per second during the supernova explosion. Here
we report the identification of the compact object in the supernova
remnant 1E 0102.2–7219 in reprocessed Chandra X-ray
Observatory data, enabled by the discovery of a ring-shaped
structure visible primarily in optical recombination lines of
Ne i and O i. The optical ring has a radius of (2.10 ± 0.35)″≡
(0.63 ± 0.11) pc, and is expanding at a velocity of 90 . 5 30
+40 − km s−1
.
It surrounds an X-ray point source with an intrinsic X-ray luminosity
Li
(1.2–2.0 keV) = (1.4 ± 0.2) × 1033 erg s−1
. The energy
distribution of the source indicates that this object is an isolated
neutron star: a central compact object akin to those
present in the Cas A3–5
and Pup A6 supernova remnants, and
the first of its kind to be identified outside of our Galaxy.
A close pair_binary_in_a_distant_triple_supermassive_black_hole_systemSérgio Sacani
This document reports the discovery of a triple supermassive black hole system through radio observations. Very Long Baseline Interferometry observations revealed two flat-spectrum radio cores, labelled J1502SE and J1502SW, within the galaxy J1502S, separated by about 140 parsecs. Analysis of archival data provides further evidence of this close black hole pair through the detection of 'S-shaped' radio emission between the two cores, indicative of jet precession caused by the binary black holes. This is the closest black hole pair yet discovered and demonstrates a new method for finding binary black holes that cannot be spatially resolved with current instruments.
A massive protocluster of galaxies at a redshift of z<5.3Sérgio Sacani
This document describes the discovery of a massive protocluster of galaxies located approximately 1 billion years after the Big Bang (redshift of z=5.3). The protocluster contains overdense regions of massive galaxies extending over 13 megaparsecs. It contains an extremely luminous starburst galaxy with large molecular gas reserves and a luminous quasar. Together, these objects place a minimum total mass of over 4×1011 solar masses in this early cluster, consistent with cosmological simulations of the earliest galaxy clusters. This discovery provides evidence for the hierarchical formation of massive structures in the early universe.
A candidate redshift z < 10 galaxy and rapid changes in that population at...Sérgio Sacani
The document summarizes the findings of a study searching for galaxies at redshift z > 10 using deep imaging data from the Hubble Ultra Deep Field. The key points are:
1) The study detects one possible galaxy candidate at z ~ 10.3, the earliest galaxy reported to date.
2) Regardless of detections, the star formation rate density is found to be much smaller (~10%) at z ~ 10 than just 200 million years later at z ~ 8, demonstrating rapid galaxy build-up in the first 500 million years.
3) The 100-200 million years before z ~ 10 appears to be a crucial phase in the early assembly of galaxies.
The ASTRODEEP Frontier Fields catalogues II. Photometric redshifts and rest f...Sérgio Sacani
This document describes a public release of photometric redshifts and galaxy properties from multi-wavelength data in the Abell-2744 and MACS-J0416 galaxy cluster fields observed as part of the Frontier Fields program. Photometric redshifts were estimated using six different methods and have an accuracy of 3-5%. Accounting for gravitational lensing magnification, the H-band number counts agree with CANDELS at bright magnitudes but extend to intrinsically fainter galaxies of H=32-33. The Frontier Fields data allow probing galaxy stellar masses 0.5-1.5 dex lower than in wide fields, including sources with masses of 107-108 solar masses at z>5. Star formation rates can be detected 1
The document discusses high energy astrophysical research conducted at the Maidanak Observatory in Uzbekistan. It provides historical context about the transfer of Islamic science to the region in the 11th century. It then describes the observatory's facilities, including its six telescopes and five CCD cameras. The main fields of scientific research at the observatory are also listed, such as gravitational lensing systems, active galactic nuclei, gamma-ray bursts, and blazars. Specific research on gravitational lensing systems and blazars using data from Maidanak is summarized.
X ray emission-from_strongly_asymmetric_circumstellar_material_in_the_remnant...Sérgio Sacani
This document summarizes a study of X-ray emission from circumstellar material (CSM) in the remnant of Kepler's supernova. The researchers used a statistical technique to isolate X-ray emission from CSM versus ejecta based on spectral characteristics. They found that most CSM is distributed along the bright north rim, but substantial amounts are also projected against the center, indicating a disk-like distribution of CSM from the progenitor system before the supernova. Hydrodynamic simulations support an AGB star companion as the origin of the asymmetric CSM. Quantitative analysis of magnesium emission identifies CSM and requires Kepler to have originated from a close binary system.
PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST/STISSérgio Sacani
Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude
region on Europa – spectroscopic detection of off-limb line emission from the dissociation
products of water. Here, we present Hubble Space Telescope (HST) direct images of Europa in
the far ultraviolet (FUV) as it transited the smooth face of Jupiter, in order to measure absorption
from gas or aerosols beyond the Europa limb. Out of ten observations we found three in which
plume activity could be implicated. Two show statistically significant features at latitudes similar
to Roth et al., and the third, at a more equatorial location. We consider potential systematic
effects that might influence the statistical analysis and create artifacts, and are unable to find any
that can definitively explain the features, although there are reasons to be cautious. If the
apparent absorption features are real, the magnitude of implied outgassing is similar to that of the
Roth et al. feature, however the apparent activity appears more frequently in our data.
A highly magnetized twin-jet base pinpoints a supermassive black holeSérgio Sacani
Supermassive black holes (SMBH) are essential for the production of jets in radio-loud active galactic nuclei (AGN). Theoretical
models based on (Blandford & Znajek 1977, MNRAS, 179, 433) extract the rotational energy from a Kerr black hole, which could
be the case for NGC1052, to launch these jets. This requires magnetic fields on the order of 103 G to 104 G. We imaged the vicinity
of the SMBH of the AGN NGC1052 with the Global Millimetre VLBI Array and found a bright and compact central feature that is
smaller than 1.9 light days (100 Schwarzschild radii) in radius. Interpreting this as a blend of the unresolved jet bases, we derive the
magnetic field at 1 Schwarzschild radius to lie between 200 G and 8:3 104 G consistent with Blandford & Znajek models.
Artigo mostra resultados obtidos com o OSIRIS que mostra manchas brilhantes na superfície do cometa 67P/Churyumov-Gerasimenko, interpretadas como sendo gelo de água e provadas via experimentos de laboratório.
A smack model_of_colliding_planetesimals_and_dust_in_the_beta_pictoris_debris...Sérgio Sacani
Uma nova simulação de supercomputador da NASA do planeta e do disco de detritos ao redor da estrela Beta Pictoris revela que o movimento do planeta dirige ondas espirais através do disco, um fenômeno que gera colisões entre os detritos em órbita. Padrões nas colisões e a poeira resultante parece ser responsável por muitas feições observadas que pesquisas anteriores tinham sido incapazes de serem explicadas completamente.
1. This document describes a multiwavelength campaign on the Seyfert 1 galaxy Mrk 509 using five satellites and two ground-based facilities.
2. The campaign aims to study several open questions about active galactic nuclei (AGN), including the location and physics of outflows from AGN, the nature of continuum emission, the geometry and physical state of the X-ray broad emission line region, and the Fe-K line complex.
3. The observations cover more than five decades in frequency, from 2 μm to 200 keV, and include a simultaneous set of deep XMM-Newton and INTEGRAL observations over seven weeks. This allows the authors to disentangle different components and study time variability
Alma observations of_feed_and_feedback_in_nearby_seyfert_galaxiesSérgio Sacani
The ALMA observations of NGC 1433 reveal a nuclear gaseous spiral structure within the central kpc. This spiral winds up into a pseudo-ring at ~200 pc from the center. Near the nucleus, there is intense high-velocity CO emission up to 200 km/s that is interpreted as an outflow, involving 3.6 million solar masses of molecular gas and a flow rate of ~7 solar masses per year. The outflow could be driven by both the central star formation and AGN through its radio jets. Continuum emission at 0.87 mm is detected only at the very center and likely comes from thermal dust emission from the molecular torus expected in this Seyfert 2 galaxy.
A rapidly spinning_supermassive_black_hole_at_the_centre_of_ngc1365Sérgio Sacani
1) XMM-Newton and NuSTAR observed the galaxy NGC 1365 simultaneously over 130 ks, detecting broadband X-ray emission from 3-79 keV.
2) The observations revealed variable absorption below 10 keV and prominent broad emission features between 5-7 keV and 10-30 keV, indicative of relativistic reflection from an accretion disk near a spinning supermassive black hole.
3) Time-resolved spectral analysis was able to disentangle the variable absorption component from the relativistic reflection component. Absorption-dominated models without reflection could be ruled out statistically and on physical grounds.
Discovery of powerful gamma ray flares from the crab nebulaSérgio Sacani
1) The AGILE satellite detected powerful gamma-ray flares from the Crab Nebula in September 2010 and October 2007 that increased the nebula's unpulsed gamma-ray flux by a factor of 3.
2) The flares originated near the nebula's central pulsar and challenge standard models of nebular emission.
3) Synchrotron emission from shock-accelerated electrons along the pulsar's polar jet can explain the gamma-ray flaring, requiring particle acceleration on timescales of about 1 day.
Rapid formation of large dust grains in the luminous supernova SN 2010jlGOASA
This document summarizes observations of rapid dust formation in the luminous supernova SN 2010jl over multiple epochs from 26 to 868 days past peak brightness. Analysis of emission line profiles shows increasing extinction over time, indicating continuous dust formation. The extinction curve implies the presence of very large (>1 micron) dust grains. Thermal emission models suggest dust temperatures declining from 2300K to 1100K over time, requiring carbonaceous rather than silicate dust. Combined extinction and emission data indicate a dust mass of ~0.0025 solar masses at 868 days, growing rapidly and expected to reach ~0.5 solar masses by 8000 days if production continues. The results provide evidence for very efficient and rapid dust formation in the dense
This document discusses using future full-sky galaxy surveys from space telescopes to probe initial conditions and constrain primordial non-Gaussianity. It proposes launching a space telescope called SPHEREx to conduct a full-sky galaxy spectroscopy survey. This would allow probing the horizon-scale clustering needed to constrain the non-Gaussianity parameter fNL using both the galaxy power spectrum and bispectrum. Current forecasts suggest SPHEREx could achieve an uncertainty of σ(fNL) ~ 0.8 from the power spectrum alone and σ(fNL) ~ 0.2 when also including the bispectrum. However, challenges remain in applying photometric redshift indicators and understanding contributions to the squeezed bispectrum at higher orders.
The document summarizes research from images taken by the New Horizons spacecraft of Charon, Pluto's largest moon. The images reveal Charon has a reddish polar cap at its north pole. Thermal models show the pole experiences long periods of extreme cold temperatures due to Charon's high obliquity and long seasons. The researchers hypothesize that methane and other volatiles escaping from Pluto's atmosphere become cold-trapped at Charon's winter pole, where they are processed by radiation into non-volatile organic compounds that remain on the surface to form the red cap. Spectral and compositional evidence supports this mechanism of seasonal accumulation of photolyzed volatiles to explain Charon's unique polar color
The open cluster_ngc6520_and_the_nearby_dark_molecular_cloud_barnard_86Sérgio Sacani
This document presents optical photometry and CO observations of the open cluster NGC 6520 and nearby dark molecular cloud Barnard 86. Analysis of the optical data finds the cluster radius is 1.0±0.5 arcmin, smaller than previous estimates. The cluster age is estimated to be 150±50 Myr with reddening of EB−V =0.42±0.10. The distance from the Sun is estimated to be 1900±100 pc, larger than previous estimates. CO observations are used to derive basic properties of Barnard 86 under the assumption it lies at the same distance as the cluster.
Two gamma ray bursts from dusty regions with little molecular gasGOASA
This document summarizes spatially-resolved observations of two gamma-ray burst (GRB) host galaxies using the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA detected molecular gas emission and dust continuum emission from the nuclear regions of both hosts. However, for one host (GRB 020819B), the GRB explosion site showed dust continuum emission but no molecular gas detection. This suggests the GRB occurred in a dust-rich region with a shortage of molecular gas, unlike typical star-forming regions. The molecular gas-to-dust ratio at the GRB site was much lower than in the host's nuclear region and the Milky Way, indicating the environment where GRBs occur
Identification of the central compact object in the young supernova remnant 1...Sérgio Sacani
Oxygen-rich young supernova remnants1
are valuable objects
for probing the outcome of nucleosynthetic processes in massive
stars, as well as the physics of supernova explosions.
Observed within a few thousand years after the supernova
explosion2
, these systems contain fast-moving oxygen-rich and
hydrogen-poor filaments visible at optical wavelengths: fragments
of the progenitor’s interior expelled at a few thousand
kilometres per second during the supernova explosion. Here
we report the identification of the compact object in the supernova
remnant 1E 0102.2–7219 in reprocessed Chandra X-ray
Observatory data, enabled by the discovery of a ring-shaped
structure visible primarily in optical recombination lines of
Ne i and O i. The optical ring has a radius of (2.10 ± 0.35)″≡
(0.63 ± 0.11) pc, and is expanding at a velocity of 90 . 5 30
+40 − km s−1
.
It surrounds an X-ray point source with an intrinsic X-ray luminosity
Li
(1.2–2.0 keV) = (1.4 ± 0.2) × 1033 erg s−1
. The energy
distribution of the source indicates that this object is an isolated
neutron star: a central compact object akin to those
present in the Cas A3–5
and Pup A6 supernova remnants, and
the first of its kind to be identified outside of our Galaxy.
A close pair_binary_in_a_distant_triple_supermassive_black_hole_systemSérgio Sacani
This document reports the discovery of a triple supermassive black hole system through radio observations. Very Long Baseline Interferometry observations revealed two flat-spectrum radio cores, labelled J1502SE and J1502SW, within the galaxy J1502S, separated by about 140 parsecs. Analysis of archival data provides further evidence of this close black hole pair through the detection of 'S-shaped' radio emission between the two cores, indicative of jet precession caused by the binary black holes. This is the closest black hole pair yet discovered and demonstrates a new method for finding binary black holes that cannot be spatially resolved with current instruments.
A massive protocluster of galaxies at a redshift of z<5.3Sérgio Sacani
This document describes the discovery of a massive protocluster of galaxies located approximately 1 billion years after the Big Bang (redshift of z=5.3). The protocluster contains overdense regions of massive galaxies extending over 13 megaparsecs. It contains an extremely luminous starburst galaxy with large molecular gas reserves and a luminous quasar. Together, these objects place a minimum total mass of over 4×1011 solar masses in this early cluster, consistent with cosmological simulations of the earliest galaxy clusters. This discovery provides evidence for the hierarchical formation of massive structures in the early universe.
A candidate redshift z < 10 galaxy and rapid changes in that population at...Sérgio Sacani
The document summarizes the findings of a study searching for galaxies at redshift z > 10 using deep imaging data from the Hubble Ultra Deep Field. The key points are:
1) The study detects one possible galaxy candidate at z ~ 10.3, the earliest galaxy reported to date.
2) Regardless of detections, the star formation rate density is found to be much smaller (~10%) at z ~ 10 than just 200 million years later at z ~ 8, demonstrating rapid galaxy build-up in the first 500 million years.
3) The 100-200 million years before z ~ 10 appears to be a crucial phase in the early assembly of galaxies.
The ASTRODEEP Frontier Fields catalogues II. Photometric redshifts and rest f...Sérgio Sacani
This document describes a public release of photometric redshifts and galaxy properties from multi-wavelength data in the Abell-2744 and MACS-J0416 galaxy cluster fields observed as part of the Frontier Fields program. Photometric redshifts were estimated using six different methods and have an accuracy of 3-5%. Accounting for gravitational lensing magnification, the H-band number counts agree with CANDELS at bright magnitudes but extend to intrinsically fainter galaxies of H=32-33. The Frontier Fields data allow probing galaxy stellar masses 0.5-1.5 dex lower than in wide fields, including sources with masses of 107-108 solar masses at z>5. Star formation rates can be detected 1
The document discusses high energy astrophysical research conducted at the Maidanak Observatory in Uzbekistan. It provides historical context about the transfer of Islamic science to the region in the 11th century. It then describes the observatory's facilities, including its six telescopes and five CCD cameras. The main fields of scientific research at the observatory are also listed, such as gravitational lensing systems, active galactic nuclei, gamma-ray bursts, and blazars. Specific research on gravitational lensing systems and blazars using data from Maidanak is summarized.
X ray emission-from_strongly_asymmetric_circumstellar_material_in_the_remnant...Sérgio Sacani
This document summarizes a study of X-ray emission from circumstellar material (CSM) in the remnant of Kepler's supernova. The researchers used a statistical technique to isolate X-ray emission from CSM versus ejecta based on spectral characteristics. They found that most CSM is distributed along the bright north rim, but substantial amounts are also projected against the center, indicating a disk-like distribution of CSM from the progenitor system before the supernova. Hydrodynamic simulations support an AGB star companion as the origin of the asymmetric CSM. Quantitative analysis of magnesium emission identifies CSM and requires Kepler to have originated from a close binary system.
PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST/STISSérgio Sacani
Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude
region on Europa – spectroscopic detection of off-limb line emission from the dissociation
products of water. Here, we present Hubble Space Telescope (HST) direct images of Europa in
the far ultraviolet (FUV) as it transited the smooth face of Jupiter, in order to measure absorption
from gas or aerosols beyond the Europa limb. Out of ten observations we found three in which
plume activity could be implicated. Two show statistically significant features at latitudes similar
to Roth et al., and the third, at a more equatorial location. We consider potential systematic
effects that might influence the statistical analysis and create artifacts, and are unable to find any
that can definitively explain the features, although there are reasons to be cautious. If the
apparent absorption features are real, the magnitude of implied outgassing is similar to that of the
Roth et al. feature, however the apparent activity appears more frequently in our data.
A highly magnetized twin-jet base pinpoints a supermassive black holeSérgio Sacani
Supermassive black holes (SMBH) are essential for the production of jets in radio-loud active galactic nuclei (AGN). Theoretical
models based on (Blandford & Znajek 1977, MNRAS, 179, 433) extract the rotational energy from a Kerr black hole, which could
be the case for NGC1052, to launch these jets. This requires magnetic fields on the order of 103 G to 104 G. We imaged the vicinity
of the SMBH of the AGN NGC1052 with the Global Millimetre VLBI Array and found a bright and compact central feature that is
smaller than 1.9 light days (100 Schwarzschild radii) in radius. Interpreting this as a blend of the unresolved jet bases, we derive the
magnetic field at 1 Schwarzschild radius to lie between 200 G and 8:3 104 G consistent with Blandford & Znajek models.
Artigo mostra resultados obtidos com o OSIRIS que mostra manchas brilhantes na superfície do cometa 67P/Churyumov-Gerasimenko, interpretadas como sendo gelo de água e provadas via experimentos de laboratório.
A smack model_of_colliding_planetesimals_and_dust_in_the_beta_pictoris_debris...Sérgio Sacani
Uma nova simulação de supercomputador da NASA do planeta e do disco de detritos ao redor da estrela Beta Pictoris revela que o movimento do planeta dirige ondas espirais através do disco, um fenômeno que gera colisões entre os detritos em órbita. Padrões nas colisões e a poeira resultante parece ser responsável por muitas feições observadas que pesquisas anteriores tinham sido incapazes de serem explicadas completamente.
A revised upper_limit_to_energy_extraction_from_a_kerr_black_holeSérgio Sacani
Uma nova simulação computacional feita pela NASA mostra que as partículas da matéria escura colidindo na extrema gravidade de um buraco negro pode produzir uma luz de raios-gamma forte e potencialmente observável. Detectando essa emissão forneceria aos astrônomos com uma nova ferramenta para entender tanto os buracos negros como a natureza da matéria escura, uma elusiva substância responsável pela maior parte da massa do universo que nem reflete, absorve ou emite luz.
A measurement of_the_black_hole_mass_in_ngc_1097_using_almaSérgio Sacani
Artigo descreve a maneira como os astrônomos usaram pela primeira vez o ALMA para medir a massa de um buraco negro supermassivo no interior de uma galáxias espiral barrada.
The mass of_the_mars_sized_exoplanet_kepler_138_b_from_transit_timingSérgio Sacani
Artigo da revista Nature, descreve o trabalho de astrônomos para medir o tamanho e a massa de um exoplaneta parecido com Marte, além de caracterizar por completo o sistema planetário da estrela Kepler-138.
The atacama cosmology_telescope_measuring_radio_galaxy_bias_through_cross_cor...Sérgio Sacani
A radiação cósmica de micro-ondas aponta para a matéria escura invisível, marcando o ponto onde jatos de material viajam a velocidades próximas da velocidade da luz, de acordo com uma equipe internacional de astrônomos. O principal autor do estudo, Rupert Allison da Universidade de Oxford apresentou os resultados no dia 6 de Julho de 2015 no National Astronomy Meeting em Venue Cymru, em Llandudno em Wales.
Atualmente, ninguém sabe ao certo do que a matéria escura é feita, mas ela é responsável por cerca de 26% do conteúdo de energia do universo, com galáxias massivas se formando em densas regiões de matéria escura. Embora invisível, a matéria escura se mostra através do efeito gravitacional – uma grande bolha de matéria escura puxa a matéria normal (como elétrons, prótons e nêutrons) através de sua própria gravidade, eventualmente se empacotando conjuntamente para criar as estrelas e galáxias inteiras.
Muitas das maiores dessas são galáxias ativas com buracos negros supermassivos em seus centros. Alguma parte do gás caindo diretamente na direção do buraco negro é ejetada como jatos de partículas e radiação. As observações feitas com rádio telescópios mostram que esses jatos as vezes se espalham por milhões de anos-luz desde a galáxia – mais distante até mesmo do que a extensão da própria galáxia.
Os cientistas esperam que os jatos possam viver em regiões onde existe um excesso de concentração da matéria escura, maior do que o da média. Mas como a matéria escura é invisível, testar essa ideia não é algo tão direto.
The build up_of_the_c_d_halo_of_m87_evidence_for_accretion_in_the_last_gyrSérgio Sacani
Observações recentes obtidas com o Very Large Telescope do ESO mostraram que Messier 87, a galáxia elíptica gigante mais próximo de nós, engoliu uma galáxia inteira de tamanho médio no último bilhão de anos. Uma equipe de astrônomos conseguiu pela primeira vez seguir o movimento de 300 nebulosas planetárias brilhantes, encontrando evidências claras deste evento e encontrando também excesso de radiação emitida pelos restos da vítima completamente desfeita.
The distribution and_annihilation_of_dark_matter_around_black_holesSérgio Sacani
Uma nova simulação computacional feita pela NASA mostra que as partículas da matéria escura colidindo na extrema gravidade de um buraco negro pode produzir uma luz de raios-gamma forte e potencialmente observável. Detectando essa emissão forneceria aos astrônomos com uma nova ferramenta para entender tanto os buracos negros como a natureza da matéria escura, uma elusiva substância responsável pela maior parte da massa do universo que nem reflete, absorve ou emite luz.
Artigo descreve como os cientistas utilizaram o Telescópio Espacial Hubble para descobrir a estratosfera num exoplaneta classificado como um Júpiter quente. Descoberta essa que pode ajudar a descobrir como os exoplanetas se formam e qual a composição de suas atmosferas.
Large heterogeneities in_comet_67_p_as_revealed_by_active_pits_from_sinkhole_...Sérgio Sacani
Em um estudo publicado online na edição da revista Nature, 18 cavidades quase circulares foram identificadas no hemisfério norte do cometa 67P/Churyumov-Gerasimenko. As cavidades tem de dezenas a centenas de metros de diâmetro e se estendem a mais de 210 metros abaixo da superfície do cometa. Essas cavidades são ativas e provavelmente criadas por um processo de sumidouro, possivelmente acompanhado por explosões.
A sonda Rosetta da ESA tem monitorado a atividade do cometa por mais de um ano, observando como seu halo de poeira e gás cresce à medida que o cometa se move para perto do Sol ao longo de sua órbita.
De uma distância de apenas centenas de quilômetros, a sonda observa um intrigante padrão de jatos de poeira sendo emitidos do núcleo enquanto eles são ejetados para o espaço.
Mas agora, graças a imagens de alta resolução da câmera de ângulo restrito da sonda, a Optical Spectroscopic and Infrared Remote Imaging System (OSIRIS), feitas de uma distância entre 10 a 30 km do centro do cometa, alguns desses jatos puderam ser rastreados de volta à superfície do cometa, chegando até a sua fonte, é a primeira vez que isso é feito e observado.
Evidence for pop_iii_like_stellar_populations_in_the_most_luminous_lyman_alph...Sérgio Sacani
Com o auxílio do Very Large Telescope do ESO, astrônomos descobriram a galáxia mais brilhante observada até hoje no Universo primordial e encontraram evidências fortes de que este objeto contém estrelas da primeira geração. Estas estrelas massivas e brilhantes, puramente teóricas até agora, foram as criadoras dos primeiros elementos pesados na história — os elementos necessários à formação das estrelas que nos rodeiam atualmente, os planetas que as orbitam e a vida tal como a conhecemos. A galáxia recentemente descoberta chamada CR7 é três vezes mais brilhante do que a galáxia distante mais brilhante que era conhecida até agora.
Os astrônomos desenvolveram há algum tempo a teoria da existência de uma primeira geração de estrelas - conhecidas por estrelas de População III — que teriam nascido do material primordial do Big Bang [1]. Todos os elementos químicos mais pesados — como o oxigênio, nitrogênio, carbono e ferro, que são essenciais à vida — formaram-se no interior das estrelas, o que significa que as primeiras estrelas se devem ter formado dos únicos elementos que existiam antes delas: hidrogênio, hélio e traços mínimos de lítio.
The dust disk_and_companion_of_the_nearby_agb_star_l2_puppisSérgio Sacani
Algumas das imagens mais nítidas obtidas com o Very Large Telescope do ESO revelaram pela primeira vez o que parece ser uma estrela velha a dar origem a uma nebulosa planetária em forma da borboleta. Estas observações da estrela gigante vermelha L2 Puppis, obtidas no modo ZIMPOL do recentemente instalado instrumento SPHERE, mostram também de forma clara uma companheira estelar próxima. As fases finais das estrelas continuam a suscitar muitas questões aos astrônomos, incluindo a origem de uma nebulosa bipolar como esta, com a sua estranha e complexa forma de ampulheta.
A cerca de 200 anos-luz de distância, L2 Puppis é uma das gigantes vermelhas mais próximas da Terra que se sabe ter atingido já as fases finais da sua vida. As novas observações obtidas com o modo ZIMPOL do SPHERE foram feitas no visível usando métodos de ótica adaptativa extremos, com os quais se corrigem as imagens com um grau muito mais elevado do que com a ótica adaptativa normal, permitindo assim que objetos tênues próximos de fontes de luz intensa possam ser observados com imenso detalhe. Tratam-se dos primeiros resultados publicados com este modo e os mais detalhados obtidos para uma estrela deste tipo.
O ZIMPOL consegue produzir imagens três vezes mais nítidas do que as obtidas com o Telescópio Espacial Hubble da NASA/ESA, sendo que as novas observações mostram a poeira que rodeia a L2 Puppis de forma extremamente detalhada [1]. Estes dados confirmam resultados anteriores, obtidos com o instrumento NACO, da poeira a formar um disco, o qual a partir da Terra nos aparece praticamente de perfil, mas dão-nos uma visão muito mais detalhada. A informação de polarização obtida com o ZIMPOL permitiu à equipa construir um modelo tridimensional das estruturas de poeira [2].
This paper analyzes NuSTAR X-ray observations of 9 optically selected type 2 quasars (QSO2s) at z < 0.5 that were candidates for being Compton-thick based on previous observations. Five new NuSTAR observations are reported. Five of the nine QSO2s were detected by NuSTAR in the 8-24 keV band, with three having sufficient counts for spectral modeling. For these three sources, NuSTAR data found their column densities were 2.5-1600 times higher and intrinsic luminosities were 10-70 times higher than previous estimates from Chandra and XMM-Newton alone. Accounting for these corrections, the authors estimate the Compton-thick fraction of optically selected type
Artigo descreve a descoberta dos astrônomos de 4 imagens de uma supernova geradas pelo efeito de lente gravitacional e formando o raro padrão da Cruz de Einstein.
The bright optical_flash_and_afterglow_from_the_gamma_ray_burst_grb_130427aSérgio Sacani
1) Researchers observed an optical flash and fading afterglow from the powerful gamma-ray burst GRB 130427A. 2) The optical and gamma-ray (>100 MeV) light curves were closely correlated during the first 7,000 seconds, best explained by reverse shock emission generated in the relativistic ejecta. 3) At later times, the optical light showed evidence of forward shock emission as it interacted with the surrounding environment.
A mildly relativistic wide-angle outflow in the neutron-star merger event GW1...Sérgio Sacani
GW170817 was the first gravitational wave detection of a binary
neutron-star merger1
. It was accompanied by radiation across the
electromagnetic spectrum and localized2
to the galaxy NGC 4993
at a distance of 40 megaparsecs. It has been proposed that the
observed γ-ray, X-ray and radio emission is due to an ultrarelativistic
jet launched during the merger, directed away from
our line of sight3–6. The presence of such a jet is predicted from
models that posit neutron-star mergers as the central engines
that drive short hard γ-ray bursts7,8
. Here we report that the radio
light curve of GW170817 has no direct signature of an off-axis
jet afterglow. Although we cannot rule out the existence of a jet
pointing elsewhere, the observed γ-rays could not have originated
from such a jet. Instead, the radio data require a mildly relativistic
wide-angle outflow moving towards us. This outflow could be the
high-velocity tail of the neutron-rich material dynamically ejected
during the merger or a cocoon of material that breaks out when a
jet transfers its energy to the dynamical ejecta. The cocoon model
explains the radio light curve of GW170817 as well as the γ-rays
and X-rays (possibly also ultraviolet and optical emission)9–15, and
is therefore the model most consistent with the observational data.
Cocoons may be a ubiquitous phenomenon produced in neutronstar
mergers, giving rise to a heretofore unidentified population of
radio, ultraviolet, X-ray and γ-ray transients in the local Universe
The broad lined_type_ic_sn_2012_ap_and_the_nature_of_relatvistic_supernovae_l...Sérgio Sacani
Artigo mostra como os astrônomos deduziram que a supernova SN 2012ap, é o elo perdido que faltava para a construção completa da árvore genealógica das supernovas.
The exceptional soft_x_ray_halo_of_the_galaxy_merger_ngc6240Sérgio Sacani
The document summarizes a recent 150-ks Chandra observation of the galaxy merger NGC 6240. Extended soft X-ray emission is detected over a 110x80 kpc region around NGC 6240. Spectral analysis finds the emission comes from hot gas with a temperature of around 7.5 million K and a total mass of about 10^10 solar masses. The gas properties suggest widespread star formation over the past 200 Myr rather than a recent nuclear starburst. The fate of the diffuse hot gas after the galaxy merger is uncertain but it may be retained and evolve into the halo of an elliptical galaxy.
A possible relativistic jetted outburst from a massive black hole fed by a t...Sérgio Sacani
1) Sw 1644+57 was detected as a gamma-ray burst but showed unusual prolonged high-energy emission, suggesting accretion onto a massive black hole.
2) Evidence points to a tidal disruption event where a star was torn apart by the black hole's strong gravity, providing an explanation for the black hole's sudden activation.
3) The emission properties and variability are consistent with a relativistic jet powered by super-Eddington accretion from the tidal disruption, analogous to a smaller-scale blazar.
The discovery of_lensed_radio_and_x-ray_sources_behind_the_frontier_fields_cl...Sérgio Sacani
We report on high-resolution JVLA and Chandra observations of the Hubble Space Telescope (HST) Frontier Cluster
MACSJ0717.5+3745. MACSJ0717.5+3745 offers the largest contiguous magnified area of any known cluster,
making it a promising target to search for lensed radio and X-ray sources. With the high-resolution 1.0–6.5 GHz
JVLA imaging in A and B configuration, we detect a total of 51 compact radio sources within the area covered by the
HST imaging. Within this sample, we find sevenlensed sources with amplification factors larger than two. None of
these sources are identified as multiply lensed. Based on the radio luminosities, the majority of these sources are
likely star-forming galaxies with star-formation rates (SFRs) of 10–50 M: yr−1 located at 1 1 z 1 2. Two of the
lensed radio sources are also detected in the Chandra image of the cluster. These two sources are likely active galactic
nuclei, given their 2–10 keV X-ray luminosities of ∼1043–44 erg s−1. From the derived radio luminosity function, we
find evidence for an increase in the number density of radio sources at 0.6 z 2.0, compared to a z 0.3 sample.
Our observations indicate that deep radio imaging of lensing clusters can be used to study star-forming galaxies, with
SFRs as low as ∼10Me yr−1, at the peak of cosmic star formation history.
An excess of_dusty_starbusts_related_to_the_spiderweb_galaxySérgio Sacani
Artigo que descreve as últimas observações do APEX revelando como se dá a formação de estrelas e a construção do Aglomerado de Galáxias da Teia de Aranha.
An excess of dusty starbursts related to the Spiderweb galaxyGOASA
This document summarizes a study that used the LABOCA instrument on the APEX telescope to observe a field around the high-redshift radio galaxy MRC1138-262 at z=2.16. 16 submillimeter galaxies (SMGs) were detected in the field, with fluxes between 3-11 mJy, indicating a density up to 4 times higher than blank field surveys. Photometric redshifts using Herschel, Spitzer, and VLT data show that at least 8 of the SMGs have z~2.2 and are part of the protocluster associated with MRC1138-262. This corresponds to a star formation rate density 1500 times higher than blank fields at this redshift, concentrated
Dissecting x ray_emitting_gas_around_the_center_of_our_galaxySérgio Sacani
1) The Chandra X-ray Observatory was used to observe the supermassive black hole at the center of the Milky Way, Sgr A*, for a total of 3 megaseconds.
2) The observations revealed extended X-ray emission around Sgr A* that aligns spatially with a surrounding disk of massive stars.
3) Spectral analysis ruled out low-mass stars as the origin of the X-ray emission and instead found evidence that the emission is from a radiatively inefficient accretion flow onto the black hole, with an outflow present.
Spectroscopic confirmation of an ultra-faint galaxy at the epoch of reionizationSérgio Sacani
Within one billion years of the Big Bang, intergalactic hydrogen
was ionized by sources emitting ultraviolet and higher energy
photons. This was the final phenomenon to globally affect all
the baryons (visible matter) in the Universe. It is referred to
as cosmic reionization and is an integral component of cosmology.
It is broadly expected that intrinsically faint galaxies
were the primary ionizing sources due to their abundance
in this epoch1,2. However, at the highest redshifts (z > 7.5;
lookback time 13.1 Gyr), all galaxies with spectroscopic confirmations
to date are intrinsically bright and, therefore, not
necessarily representative of the general population3. Here,
we report the unequivocal spectroscopic detection of a low
luminosity galaxy at z > 7.5. We detected the Lyman-α emission
line at ∼10,504 Å in two separate observations with
MOSFIRE4 on the Keck I Telescope and independently with
the Hubble Space Telescope’s slitless grism spectrograph,
implying a source redshift of z = 7.640 ± 0.001. The galaxy
is gravitationally magnified by the massive galaxy cluster
MACS J1423.8+2404 (z = 0.545), with an estimated intrinsic
luminosity of MAB = −19.6 ± 0.2 mag and a stellar mass of
☆ = × − +
M 3.0 0.8 10
1.5 8 solar masses. Both are an order of magnitude
lower than the four other Lyman-α emitters currently
known at z > 7.5, making it probably the most distant representative
source of reionization found to date.
Probing the innermost_regions_of_agn_jets_and_their_magnetic_fields_with_radi...Sérgio Sacani
Desde 1974, observações feitas com o chamado Long Baseline Interferometry, ou VLBI, combinaram sinais de um objeto cósmico recebidos em diferentes rádio telescópios espalhados pelo globo para criar uma antena com o tamanho equivalente à maior separação entre elas. Isso fez com que fosse possível fazer imagens com uma nitidez sem precedentes, com uma resolução 1000 vezes melhor do que Hubble consegue na luz visível. Agora, uma equipe internacional de astrônomos quebrou todos os recordes combinando 15 rádio telescópios na Terra e a antena de rádio da missão RadioAstron, da agência espacial russa, na órbita da Terra. O trabalho, liderado pelo Instituto de Astrofísica de Andalucía, o IAA-CSIC, forneceu novas ideias sobre a natureza das galáxias ativas, onde um buraco negro extremamente massivo engole a matéria ao redor enquanto simultaneamente emite um par de jatos de partículas de alta energia e campos magnéticos a velocidades próximas da velocidade da luz.
Observações feitas no comprimento de onda das micro-ondas são essenciais para explorar esses jatos, já que os elétrons de alta energia se movendo em campos magnéticos são mais proficientes em produzir micro-ondas. Mas a maioria das galáxias ativas com jatos brilhantes estão a bilhões de anos-luz de distância da Terra, de modo que esses jatos são minúsculos no céu. Desse modo a alta resolução é essencial para observar esses jatos em ação e então revelar fenômenos como as ondas de choque e a turbulência que controla o quanto de luz é produzida num dado tempo. “Combinando pela primeira vez rádio telescópios na Terra com rádio telescópios no espaço, operando na máxima resolução, tem permitido que a nossa equipe crie uma antena que tem um tamanho equivalente a 8 vezes o diâmetro da Terra, correspondendo a 20 micro arcos de segundo”, disse José L; Gómez, o líder da equipe no Instituto de Astrofísica de Andalucía, IAA-CSIC.
This document summarizes research using pulsar timing array data to search for gravitational waves from binary supermassive black holes. The authors analyzed 11 years of timing data for 4 millisecond pulsars and placed an upper limit on the characteristic strain amplitude of the gravitational wave background of Ac,yr < 1.0×10-15 at 95% confidence. This limit is inconsistent with current models of binary supermassive black hole evolution and gravitational wave emission. It suggests binary evolution may be more efficient than assumed or the gravitational wave background is weaker than predicted. Improved pulsar timing data could help distinguish between possible explanations for the non-detection.
This document provides a multiwavelength summary of GRB 130427A, one of the brightest gamma-ray bursts ever detected. It was observed across the electromagnetic spectrum from gamma-rays to radio wavelengths. Key points:
1) GRB 130427A had an extremely high luminosity and energy release, similar to the most powerful high-redshift bursts.
2) Follow-up observations detected associated supernova SN 2013cq, showing that very energetic bursts can still be accompanied by supernovae.
3) Light curves at X-ray, optical, and ultraviolet wavelengths show evidence for a jet break approximately 37 kiloseconds after the burst.
4) Standard synchrotron shock models
No signature of_ejecta_interaction_with_a_stellar_companion_in_three_type_ia_...Sérgio Sacani
ARtigo descreve estudos de supernovas feitos com o Kepler e mostram que explosões podem ser geradas por estrelas anãs brancas simples, se chocando com outras ou se fundindo com outras.
Black hole growth in the early universe is self regulated and largely hidde...Sérgio Sacani
The study analyzed X-ray data from the Chandra X-ray Observatory to measure black hole growth in galaxies between redshifts 6-8 (0.95-0.7 billion years after the Big Bang). It found:
1) A stacked signal from 197 galaxies at z<6 detected significant X-ray emission, implying black holes grew in tandem with their host galaxies throughout cosmic history.
2) Most vigorously accreting black holes at these early epochs were obscured by significant gas and dust, absorbing most radiation except high-energy X-rays.
3) The obscured black hole growth suggests growth was significantly more than previously thought, but the obscuration prevented contribution to reionizing the Universe.
A spectroscopic sample_of_massive_galaxiesSérgio Sacani
This document describes a study of 16 massive galaxies at z ~ 2 selected from the 3D-HST spectroscopic survey based on the detection of a strong 4000 Angstrom break in their spectra. Spectroscopy and imaging from HST/WFC3 are used to determine accurate redshifts, stellar population properties, and structural parameters. The sample significantly increases the number of spectroscopically confirmed evolved galaxies at z ~ 2 with robust size measurements. The analysis populates the mass-size relation and finds it is consistent with local relations but with smaller sizes by a factor of 2-3. A model is presented where the observed size evolution is explained by quenching of increasingly larger star-forming galaxies at a rate set by
Monthly quasi-periodic eruptions from repeated stellar disruption by a massiv...Sérgio Sacani
In recent years, searches of archival X-ray data have revealed galaxies
exhibiting nuclear quasi-periodic eruptions with periods of several hours.
These are reminiscent of the tidal disruption of a star by a supermassive
black hole. The repeated, partial stripping of a white dwarf in an eccentric
orbit around an ~105 M⊙ black hole provides an attractive model. A separate
class of periodic nuclear transients, with much longer timescales, have
recently been discovered optically and may arise from the partial stripping
of a main-sequence star by an ~107 M⊙ black hole. No clear connection
between these classes has been made. We present the discovery of an X-ray
nuclear transient that shows quasi-periodic outbursts with a period of
weeks. We discuss possible origins for the emission and propose that this
system bridges the two existing classes outlined above. This discovery was
made possible by the rapid identifcation, dissemination and follow-up
of an X-ray transient found by the new live Swift-XRT transient detector,
demonstrating the importance of low-latency, sensitive searches for
X-ray transients.
A dust-enshrouded tidal disruption event with a resolved radio jet in a galax...Sérgio Sacani
Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the
gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the
western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg in the infrared and radio
but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission
reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the
difference between theoretical predictions and observed luminosities of TDEs. The radio observations
resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.
Similar to A very luminous_magnetar_powered_supernova_associated_with_an_ultra_long_gamma_ray_burst (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.
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 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.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
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.
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
II. Syntrophism:
It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
i. Methanogenic ecosystem in sludge digester
Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
ii. Lactobacillus arobinosus and Enterococcus faecalis:
In the minimal media, Lactobacillus arobinosus and Enterococcus faecalis are able to grow together but not alone.
The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
This presentation offers a general idea of the structure of seed, seed production, management of seeds and its allied technologies. It also offers the concept of gene erosion and the practices used to control it. Nursery and gardening have been widely explored along with their importance in the related domain.
Embracing Deep Variability For Reproducibility and Replicability
Abstract: Reproducibility (aka determinism in some cases) constitutes a fundamental aspect in various fields of computer science, such as floating-point computations in numerical analysis and simulation, concurrency models in parallelism, reproducible builds for third parties integration and packaging, and containerization for execution environments. These concepts, while pervasive across diverse concerns, often exhibit intricate inter-dependencies, making it challenging to achieve a comprehensive understanding. In this short and vision paper we delve into the application of software engineering techniques, specifically variability management, to systematically identify and explicit points of variability that may give rise to reproducibility issues (eg language, libraries, compiler, virtual machine, OS, environment variables, etc). The primary objectives are: i) gaining insights into the variability layers and their possible interactions, ii) capturing and documenting configurations for the sake of reproducibility, and iii) exploring diverse configurations to replicate, and hence validate and ensure the robustness of results. By adopting these methodologies, we aim to address the complexities associated with reproducibility and replicability in modern software systems and environments, facilitating a more comprehensive and nuanced perspective on these critical aspects.
https://hal.science/hal-04582287
A very luminous_magnetar_powered_supernova_associated_with_an_ultra_long_gamma_ray_burst
1. 1
A very luminous magnetar-powered supernova associated with an
ultra-long gamma-ray burst
Jochen Greiner1,2
, Paolo A. Mazzali3,4
, D. Alexander Kann5
, Thomas Krühler6
, Elena Pian7,8
,
Simon Prentice3
, Felipe Olivares E.9
, Andrea Rossi5,7
, Sylvio Klose5
, Stefan Taubenberger4,10
,
Fabian Knust1
, Paulo M.J. Afonso11
, Chris Ashall3
, Jan Bolmer1,12
, Corentin Delvaux1
, Roland
Diehl1
, Jonathan Elliott1,17
, Robert Filgas13
, Johan P.U. Fynbo14
, John F. Graham1
, Ana Nicuesa
Guelbenzu5
, Shiho Kobayashi3
, Giorgos Leloudas14,15
, Sandra Savaglio1,16
, Patricia Schady1
,
Sebastian Schmidl5
, Tassilo Schweyer1,12
, Vladimir Sudilovsky1,17
, Mohit Tanga1
, Adria C.
Updike18
, Hendrik van Eerten1
, Karla Varela1
1
Max-Planck Institut für Extraterrestrische Physik, Giessenbachstr. 1, 85748 Garching, Germany
2
Excellence Cluster Universe, Technische Universität München, Boltzmannstr. 2, 85748,
Garching, Germany
3
Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science
Park, 146 Browlow Hill, Liverpool L3 5RF, United Kingdom
4
Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
5
Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
6
European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19,
Chile
7
INAF, Institute of Space Astrophysics and Cosmic Physics, via P. Gobetti 101, 40129 Bologna,
Italy
8
Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
9
Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago,
Chile
10
European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
11
American River College, Physics & Astronomy Dpt., 4700 College Oak Drive, Sacramento, CA
95841, USA
12
Technische Universität München, Physik Dept., James-Franck-Str., 85748 Garching, Germany
13
Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska
3a/22, 128 00 Prague 2, Czech Republic
14
DARK Cosmology Center, Niels-Bohr-Institut, University of Copenhagen, Juliane Maries Vej
30, 2100 København, Denmark
15
Department of Particle Physics & Astrophysics, Weizmann Institute of Science, Rehovot
76100, Israel
16
Universita della Calabria, 87036 Arcavacata di Rende, via P. Bucci, Italy
17
Astrophysics Data System, Harvard-Smithonian Center for Astrophysics, Garden St. 60,
Cambridge, MA 02138, U.S.A.
18
Roger Williams University, 1 Old Ferry Rd, Bristol, RI 02809, U.S.A.
2. 2
A new class of ultra-long duration (>10,000 s) gamma-ray bursts has recently been
suggested1,2,3
. They may originate in the explosion of stars with much larger radii than
normal long gamma-ray bursts3,4
or in the tidal disruptions of a star3
. No clear supernova
had yet been associated with an ultra-long gamma-ray burst. Here we report that a
supernova (2011kl) was associated with the ultra-long duration burst 111209A, at z=0.677.
This supernova is more than 3 times more luminous than type Ic supernovae associated with
long gamma-ray bursts5,6,7
, and its spectrum is distinctly different. The continuum slope
resembles those of super-luminous supernovae8,9
, but extends farther down into the
rest-frame ultra-violet implying a low metal content. The light curve evolves much more
rapidly than super-luminous supernovae. The combination of high luminosity and low
metal-line opacity cannot be reconciled with typical type Ic supernovae, but can be
reproduced by a model where extra energy is injected by a strongly magnetized neutron star
(a magnetar), which has also been proposed as the explanation for super-luminous
supernovae10
.
3. 3
The gamma-ray burst (GRB) 111209A was detected by the Swift satellite at 07:12 UT on
December 9, 2011. The X-ray and optical counterparts were discovered within minutes of the
trigger11
. The extraordinarily long duration of GRB 111209A was revealed by the continuous
coverage with the Konus detector on the WIND spacecraft12
, extending from 5400s before to
10000s after the Swift trigger. The GRB occurred at a redshift of z=0.677, as determined from
afterglow spectroscopy3
. Its integrated equivalent isotropic energy output, Eiso =
(5.70.7)1053
erg 12
, lies at the bright end of the distribution of long-duration GRBs.
The afterglow of GRB 111209A was observed over a period of about 70 days with the 7-channel
optical/near-infrared imager GROND13
. Starting around day 15, the optical light curve of the
transient deviated from the earlier afterglow power law decay (Figure 1). The light curve remained
essentially flat between day 15 and 30, and then started to decay again, approaching the
host-galaxy level. After subtracting the afterglow and the well-modelled host galaxy emission
(Methods, §1-§3), the excess emission is well constrained between rest-frame day 6 and 43 after
the GRB (Figure 2). It is very similar in shape to other GRB-related supernovae (SN), but reaches
a bolometric peak luminosity of 2.8+1.2
-1.0 x 1043
erg/s (corresponding to Mbol
=20.0 mag) at 14
rest-frame days, a factor 3 higher than the brightest known GRB-SN (Figure 2).
A VLT/X-shooter spectrum was taken near the peak of the excess emission3
(Dec. 29, 2011), 11.8
rest-frame days after the GRB. The afterglow and the (minimal) host contribution were subtracted
(Methods, §3) and the resulting spectrum is shown in Figure 3 (blue line). The strong similarity of
the evolution in time and colour to GRB-associated SNe, together with the spectral shape of the
excess emission, leads us to conclude that this emission is caused by a supernova, designated SN
2011kl, associated with GRB 111209A.
Canonical long-duration GRBs are generally accepted to be linked to the core collapse of massive
stars stripped of their outer H and He envelopes5,6,7
, since every spectroscopically confirmed
supernova associated with a GRB has been a broad-lined SNIc so far. Although the spectrum of
SN 2011kl associated with the ultra-long GRB 111209A also shows no H or He, it is substantially
different from classical GRB-SNe. It is surprisingly featureless redwards of 300nm, lacking the
undulations from spectral line blends typical of broad-lined SNeIc associated with GRBs5,6,7
, and
it does not drop in the 300–400nm (rest-frame) region (Figure 3), suggesting a very low metal
abundance. Applying standard parametrized SN light curve fits (Methods, §4), we derive an ejecta
mass Mej = 31 M⊙ and a 56
Ni mass of 1.00.1 M⊙, which implies a very high 56
Ni/Mej ratio. This
large 56
Ni mass is not compatible with the spectrum, suggesting that 56
Ni is not responsible for the
luminosity, unlike canonical stripped-envelope SNe (Methods, §4).
Various models have been suggested to explain the ultra-long duration of GRB 111209A and other
ULGRBs, but the otherwise inconspicuous spectral and timing properties of both the prompt and
afterglow emission as well as the host properties provided no obvious clues1-4,14-16
. With the
detection of a supernova associated with the ultra-long GRB 111209A, we can immediately
discard a tidal disruption interpretation3
. Known supernovae from blue supergiants show hydrogen
in their spectra and substantially different light curve properties17
, inconsistent with our
observations, thus ruling out a blue supergiant progenitor4
. Finally, additional emission from the
interaction of the SN ejecta with circum-stellar material is unlikely as well (Methods, §5).
Our data suggest that SN 2011kl is intermediate between canonical overluminous GRB-SNe
and super-luminous supernovae (SLSNe; Figure 3). SLSNe are a sub-class of SNe which are a
4. 4
factor 100 brighter than normal core-collapse SNe, reaching MV
~ 21 mag 8,9
. They show slow
rise and late peak times (20–100 days as compared to typically 9–18 days). Their spectra are
characterized by a blue continuum with a distinctive “W”-shaped spectral feature often interpreted
as OII lines8
. A spinning-down magnetic neutron star is the favoured explanation for the energy
input powering the light curve10
. The comparison of SN 2011kl with SLSNe is motivated by two
observational facts: (1) the spectrum is a blue continuum, extending far into the rest-frame UV, and
(2) the peak luminosity is intermediate between GRB-SNe and SLSNe. Our interpretation is
motivated by the failure of both the collapsar and the standard fall-back accretion scenarios,
because in these cases the engine quickly runs out of mass for any reasonable accretion rate and
mass reservoir, and thus is unlikely to be able to power an ultra-long GRB.
We could reproduce the spectrum of SN 2011kl using a radiation transport code18,19
and a density
profile where r7
, which is typical of the outer layers of SN explosions. The UV is significantly
depressed relative to a blackbody, but much less depressed than in the spectra of GRB-SNe,
indicating a lower metal content (consistent with 1/4 of the solar metallicity). The spectrum
appears rather featureless owing to line blending. This follows from the high photospheric
velocity, vph ~ 20,000km/s (Figure 3). In contrast, SLSNe, which show more line features, have vph
~ 10,000km/s. In the optical, on the other hand, only a few very weak absorption lines are visible in
our SN spectrum. Our model only has 0.4M⊙ of material above the photosphere. There is no
evidence of freshly synthesized material mixed-in, unlike in GRB-SNe. This supports the notion
that the SN light curve was not powered by 56
Ni decay but rather by a magnetar.
The spectrum can be reproduced without invoking interaction, and the low metal abundance
suggests that it is unlikely that much 56
Ni was produced. We therefore consider magneto-rotational
energy input as the source of luminosity. Using a simple formalism20
describing rotational energy
loss via magnetic dipole radiation, and relating the spin-down rate to the effective radiative
diffusion time, one can infer the magnetar’s initial spin period, Pi
and magnetic dipole field
strength B from the observed luminosity and time to light-curve peak, tpeak
. The observed short
tpeak
(14 rest-frame days) and the moderate peak luminosity require a magnetar with initial spin
period Pi ~ 12 ms for a magnetic field strength of (69)1014
G. Depending on the magnetic field,
ejecta mass and kinetic energy are relatively uncertain ranging between 2 and 3 M⊙ and
(29)1051
erg, respectively (Methods, §6). These values are actually more typical of normal
SNeIb/c than of GRB-SNe, including SN2006aj, the first SN identified as magnetar-powered21
.
The GRB energy can be reconciled with the maximum energy that can be extracted from a
magnetar if the correction for collimation of the GRB jet is a factor of 1/50 or less, which is well
within typical values for GRBs22
.
The idea of a magnetar as the inner engine powering GRB-SNe23,24
, SLSNe10
, or even events like
Swift 1644+57 25
(before consensus for this event favoured a relativistic tidal disruption), is not
new. However, in all these cases the magnetar interpretation was one of several options providing
reasonable fits to the data, but never cogent. Also, the suggestion that all GRB-SNe are
magnetars24
rather than collapsars, based on the clustering of the kinetic energy of the GRB-SNe
near 1052
erg, the rotational power of a millisecond neutron star, was only circumstantial evidence.
The supernova SN 2011kl is clearly different from canonical GRB-SNe, and requires (rather than
only allows) a new explanation.
The ultra-long duration of the prompt emission of GRB 111209A and the unusual SN properties
are probably related. We suggest that they are linked to the birth and subsequent action of a
5. 5
magnetar following the collapse of a massive star. The magnetar re-energizes the expanding ejecta
and powers an over-luminous supernova. This particular SN 2011kl was not quite as luminous as
typical SLSNe, and it may represent a population of events that is not easily discovered by SN
searches but may have a relatively high rate. This scenario offers a link between GRB-SNe,
ultra-long GRBs and SLSNe.
References
[1] Gendre, B. et al. The ultra-long gamma-ray burst 111209A: the collapse of a blue supergiant?
Astrophys. J. 766, A30 (2013)
[2] Stratta, G. et al. The ultra-long gamma-ray burst 111209A: II. Prompt to afterglow and afterglow
properties. Astrophys. J. 779, A66 (2013)
[3] Levan, A. et al. A new population of ultra-long duration gamma-ray bursts. Astrophys. J. 781, A13
(2014)
[4] Nakauchi, D., Kashiyama, K., Suwa, Y., Nakamura, T., Blue supergiant model for ultra-long
gamma-ray bursts with superluminous-supernova-like bump. Astrophys. J. 778, A67 (2013)
[5] Galama, T., Vreeswijk, P.M., van Paradijs, J. et al. An unusual supernova in the error box of the
gamma-ray burst of 25 April 1998. Nature 395, 670–672 (1998)
[6] Hjorth, J. et al. A very energetic supernova associated with the gamma-ray burst of 29 March 2003.
Nature 423, 847–850 (2003)
[7] Stanek, K.Z. et al. Spectroscopic discovery of the supernova 2003dh associated with GRB 030329.
Astrophys. J. 591, L17–L20 (2003)
[8] Quimby, R.M. et al. Hydrogen-poor superluminous stellar explosions. Nature 474, 487–489 (2011)
[9] Gal-Yam, A. Luminous Supernovae. Science 337, 927–932 (2012)
[10] Dessart, L., Hillier, D.J., Waldman, R., Livne, E., Blondin, S. Superluminous supernovae: 56
Ni power
versus magnetar radiation. Mon. Not. R. Astron. Soc. 426, L76–L80 (2012)
[11] Hoversten, E.A. et al. GRB 111209A: Swift detection of a long burst with an optical counterpart. GCN
Circular #12632 (2011)
[12] Golenetskii, S. et al. Konus-Wind observation of GRB 111209A. GCN Circular #12663 (2011)
[13] Greiner, J. et al. GROND - a 7-channel imager. Publ. Astron. Soc. Pac. 120, 405–424 (2008)
[14] Virgili, F.J. et al. GRB 091024A and the nature of ultra-long gamma-ray bursts. Astrophys. J. 778, A54
(2013)
[15] Zhang, B.-B., Zhang, B., Murase, K., Connaughton, V., Briggs, M.S. How long does a burst burst?
Astrophys. J. 787, A66 (2014)
[16] Leloudas, G., et al. Spectroscopy of superluminous supernova host galaxies. A preference of
hydrogen-poor events for extreme emission line galaxies. Mon. Not. R. Astron. Soc. 449, 917‒932
(2015)
[17] Kleiser, I.K.W. et al. Peculiar Type II supernovae from blue supergiants. Mon. Not. R. Astron. Soc.
415, 372–382 (2011)
[18] Mazzali, P.A., Lucy, L.B. The application of Monte Carlo methods to the synthesis of early-time
supernovae spectra. Astron. Astrophys. 279, 447–456 (1993)
[19] Mazzali, P. A. Applications of an improved Monte Carlo code to the synthesis of early-time Supernova
spectra. Astron. Astrophys. 363, 705–716 (2000)
[20] Kasen, D., Bildsten, L. Supernova light curves powered by young magnetars. Astrophys. J. 717, 245–
249 (2010)
[21] Mazzali, P. et al. A neutron-star-driven X-ray flash associated with supernova SN 2006aj. Nature 442,
1018–1020 (2006)
[22] Ryan, G., van Eerten, H., MacFadyen, A., Zhang, B.-B. Gamma-Ray Bursts are observed off-axis.
Astrophys. J. 799, A3 (2015)
[23] Cano, Z. A trio of gamma-ray burst supernovae: GRB 120729A, GRB 130215A/SN 2013ez, and GRB
130831A/SN 2013fu. Astron. Astrophys. 568, A19 (2014)
[24] Mazzali, P. A. et al. An upper limit to the energy of gamma-ray bursts indicates that GRBs/SNe are
powered by magnetars. Mon. Not. R. Astron. Soc. 443, 67–71 (2014)
6. 6
[25] Quataert, E., Kasen, D. Swift 1644+57: the longest gamma-ray burst? Mon. Not. R. Astron. Soc. 419,
L1–L5 (2012)
[26] Sauer, D.N. et al. The properties of the ’standard’ type Ic supernova 1994I from spectral models. Mon.
Not. R. Astron. Soc. 369, 1939–1948 (2006)
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A128 (2013)
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galaxy. Astrophys. J. 771, A97 (2013)
[29] Vreeswijk, P.M., et al. The hydrogen-poor superluminous supernova iPTF 13ajg and its host galaxy in
absorption and emission. Astrophys. J. 797, A24 (2014)
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Pac. 124, 668–681 (2012)
Supplementary Information is linked to the online version of that paper at
www.nature.com/nature.
Acknowledgements. We are grateful to R. Lunnan and E. Berger for providing the spectrum of
PS1-10bzj in digital form, and to A. Levan for the HST grism spectra of GRB 111209A. JG, ROD
and DAK acknowledge support by the DFG cluster of excellence “Origin and Structure of the
Universe” (www.universe-cluster.de). PS, JFG and MT acknowledge support through the Sofja
Kovalevskaja award to P. Schady from the Alexander von Humboldt Foundation Germany. CD
acknowledges support through EXTraS, funded from the European Union’s Seventh Framework
Programme for research, technological development and demonstration. SK, DAK and ANG
acknowledge support by DFG. SSc acknowledges support by the Thüringer Ministerium für
Bildung, Wissenschaft und Kultur. FOE acknowledges support from FONDECYT. ST is
supported by DFG. Part of the funding for GROND (both hardware as well as personnel) was
generously granted from the Leibniz-Prize to G. Hasinger. DARK is funded by the DNRF.
Author contributions. JG has led the observing campaign and the paper writing. DAK was
responsible for the GROND data reduction, and performed the fitting of the afterglow light curve.
FK derived the accurate GROND astrometry, PS the UVOT photometry, and AR the host fitting.
PM suggested the magnetar interpretation and computed the spectral models. SP and CA
performed the light-curve model fitting. FOE and EP assisted in spectral decomposition and the
construction of the bolometric light curve. ST, SK, and GL provided crucial input and discussion.
DAK, ANG, PMJA, JB, CD, JE, RF, JFG, SSc, TS, VS, MT, ACU and KV were performing the
many epochs of GROND observations. TK, JPUF and GL provided and analysed the X-shooter
spectrum. SSa, SK, RD, HvE have been instrumental in various aspects of the data interpretation.
Author Information. Reprints and permissions information is available at
www.nature.com/reprints. The authors declare no competing financial interests. Correspondence
and requests for materials should be addressed to jcg@mpe.mpg.de.
7. 7
Figure 1: Observed optical/near-infrared light curve following GRB 111209A.
The light curve (GROND data: filled symbols; other data: open symbol) is the sum of the afterglow
of GRB 111209A modelled by a broken power law (dashed line), the accompanying supernova
2011kl (thin red line) and the constant GRB/SN host galaxy emission (horizontal dotted line). All
measurements are relative to the Swift trigger time and as observed, apart from the Vega-to-AB
transformation for the J-band. The solid violet line is the sum of afterglow and host in the u-band,
with no sign of the supernova. The solid red line is the sum of afterglow, host and supernova for the
r΄-band. The vertical dotted line marks the time of the VLT/X-shooter spectrum.
Figure 2: Light curve of the GRB 111209A supernova SN 2011kl.
Bolometric light curve of SN 2011kl, corresponding to 230–800 nm rest frame (Methods, §1),
compared with those of GRB 980425 / SN 1998bw 5
, XRF 060218 / SN 2006aj 21
, the standard
type Ic SN 1994I 26
, and the SLSNe PTF11rks 27
and PS1-10bzj 28
(among the fastest-declining
SLSNe known so far), all integrated over the same wavelength band. Solid lines show the
best-fitting synthetic light curves computed with a magnetar injection model20
(dark blue;
Methods, §6) and 56
Ni powering (light blue; Methods, §4), respectively.
Figure 3: Spectra comparison.
The X-shooter spectrum of SN 2011kl, taken on Dec. 29, 2011 after GRB afterglow and host
subtraction and moderate rebinning (Methods, §1; ED Fig. 2), with its flat shape and high UV flux
is distinctly different from the hitherto brightest known GRB-SN 1998bw (red), but reminiscent of
some SLSNe (top three curves)28-30
. The three grey/black lines show synthetic spectra with
different photospheric velocities (as labelled), demonstrating the minimum velocity required to
broaden unseen absorption around 400 nm rest-frame (CaII, CII), but at the same time explain the
sharp cut-off below 280 nm rest-frame. The y-scale is correct for SNe 2011kl and 1998bw; all
other spectra are shifted for display purposes.
8. 8
Table 1: AB Magnitudes of SN 2011kl associated with GRB 111209A.
t [s] g΄ mag r΄ mag i΄ mag z΄ mag
843664 24.36
+0.26
0.21 23.92
+0.23
0.19 24.03
+0.55
0.38 23.97
+1.13
0.57
1101930 24.17
+0.29
0.24 23.66
+0.16
0.14 23.80
+0.44
0.33 23.83
+0.75
0.48
1358649
1360463 23.28
+0.12
0.11
1361742 23.16
+0.28
0.25
1705078 23.590.04
1706253 22.990.04
1880549 23.470.15 22.900.07 22.740.13 22.78
+0.19
0.18
2049952
2401323 23.53
+0.28
0.27
23.250.15 22.900.17 22.67
+0.23
0.22
2664187
3037306
3085966
3090966 23.88
+0.18
0.17
23.210.11 23.05
+0.17
0.16
22.700.19
3518554
3692304 23.350.12
3693574 23.21
+0.23
0.22
3694905 24.360.07
3696071 23.600.05
3950847
4258444 24.41
+0.39
0.37
23.800.20 23.63
+0.42
0.40 23.44
+0.62
0.58
4732196 24.69
+0.63
0.58 24.28
+0.27
0.26 23.80
+0.32
0.31 23.67
+0.48
0.46
6241880 25.26
+0.84
0.74 24.29
+0.78
0.73 24.27
+1.57
1.34
The data are corrected for the GRB afterglow and host-galaxy contributions, as well as Galactic
foreground and rest-frame extinction. The times are in the observer frame. The magnitudes without
contemporaneous g΄r΄i΄z΄-magnitudes are taken from [3].
9. 9
Methods
1. Observations and Data Analysis
Simultaneous imaging in g'r'i'z'JHKs
with the 7-channel imager GROND13
was done on 16 epochs
with logarithmic temporal spacing until 72 days after the GRB, when the nearby Sun prevented
further observations, and a last epoch for host photometry was obtained 280 days after the GRB
(Extended Data Table 1). GROND data have been reduced in the standard manner using
pyraf/IRAF31,32,33
. The optical imaging was calibrated against comparison stars obtained by
observing a nearby SDSS field (immediately before the afterglow observation in the third night
under photometric conditions) and calibrated against the primary SDSS34
standard star network.
The NIR data were calibrated against the 2MASS catalog. This results in typical absolute
accuracies of 0.03 mag in g΄r΄i΄z΄ and 0.05 mag in JHKS (1σ errors are reported everywhere).
All GROND measurements are listed in Extended Data Table 1, and the properties of the GRB
afterglow proper, including the two kinks in the early afterglow light curve (Fig. 1) will be
described in detail elsewhere [Kann, D.A. et al. 2015, Astron. Astrophys. (in prep.)].
We have made use of two other sources of measurements: First, we add u-band observations
obtained with Swift/UVOT (Extended Data Table 2). UVOT photometry was carried out on
pipeline-processed sky images downloaded from the Swift data centre35
following the standard
UVOT procedure36
, and is fully compatible with earlier, independent publications of the UVOT
data2,3
. Second, we add selected complementary data3
, in particular (i) HST F336W/F125W data
from 11.1 and 35.1 days after the GRB, respectively; (ii) two epochs of VLT/FORS2 g΄RCi΄z΄ data
during the SN phase, which agree excellently with our data due to their use of our GROND
calibration stars; (iii) a late-time Gemini-S u΄-band observation (198 days after the GRB).
With the constant host galaxy contribution accurately determined at late times in u΄g΄r΄i΄z΄J (see §3
and Extended Data Fig. 4), the afterglow light curve shows clear evidence for a steeper afterglow
decay at >10 days post-burst, particularly in the u΄-band where there is essentially no contribution
from the supernova (as evidenced by the spectrum) and which therefore can be used as a template
for the pure afterglow contribution. We link the decay slopes for all filters to be the same. This
provides the two decay slopes α1=1.55±0.01 and α2=2.33±0.06, with a break time of tb=9.21±0.47
days. The u΄-band fit is also shown in Figure 1 to visualize the decomposition. Apart from our
much larger data set provided by our GROND observations, the difference to the decomposition of
[3] is the fact that they ignored the host contribution in the redder bands at 3050 days (though
they actually note this in their work).
In order to create the SN light curve for each photometric band, we then subtracted both, the
afterglow contribution in that band based on the extrapolation of the afterglow light curve, and the
host galaxy contribution based on its spectral energy distribution; see §3. The error in the host
galaxy subtraction is negligible as the host photometry is accurate to better than 10%, and the host
contributes only between 5–15% to the total light during the SN bump. The error on the afterglow
subtraction depends on whether or not the decay slope 2
remained constant after the last secure
measurement right before the onset of the SN. The intrinsic GRB afterglow light curves at this late
time are observed to only steepen, never flatten. Thus, our afterglow subtraction is conservative,
and results in a lower limit for the SN luminosity.
10. 10
The quasi-bolometric light curve of SN 2011kl was constructed from GROND g΄r΄i΄z΄J
photometry and the supplementary data3
as follows. First, the individual filter bands have been
extinction-corrected with AV
Gal
= 0.06 mag Galactic foreground37
, and rest-frame AV
Host
= 0.12
mag as derived from the GRB afterglow spectral energy distribution fitting. By deriving quadratic
polynomials for sets of three consecutive filters (Simpson’s rule) they were then combined to
create a quasi-bolometric light curve.
The quadratic polynomials are then integrated over rest-frame wavelength from 3860/(1+z) Å
(blue edge of the g΄-band filter) to 13560/(1+z) Å (red edge of the J filter). The k-correction was
computed from the spectral energy distribution. In order to transform the integrated flux into
luminosity, we employed a luminosity distance of d=4080 Mpc, using concordance cosmology
(
=0.73, m
=0.27, and H0
=71 km s1
Mpc1
).
No correction for the contribution of the unobserved near-infrared part of the spectrum has been
applied to both, SN 2011kl and SN 1998bw (Figure 2), because this emission is usually sparsely
sampled in wavelength and time, and thus is largely based on assumptions (and no data is available
for the plotted SLSNe). For SN 2011kl we lack any rest-frame near-infrared measurements. We
acknowledge that therefore the bolometric luminosity might be underestimated by 5%–30%. Other
than that, all bolometric light curves shown in Fig. 2 are integrated over the same wavelength band
(except for the UV band, which contributes less than a few percent at and after maximum). The
SLSN light curves are plotted according to the observational constraints of their maxima, i.e.
g-band peak at 16.8 days rest-frame for PTF11rks 27
and using the first measurement 17.5 days
before maximum as lower limit for PS1-10bzj 28
.
The VLT/X-shooter38
spectrum, taken on Dec. 29, 2011 (19.8 days after the GRB, 11.8 rest-frame
days, and 2 days prior to the SN maximum), has been reduced with the ESO X-shooter pipeline
v2.2.0, in particular for flat-fielding, order tracing, rectification and initial wavelength calibration
with an arc lamp. During rectification, a dispersion of 0.4Å/pixel has been used in the UVB/VIS
arm, minimizing correlated noise but maintaining sufficient spectral resolution for resolving lines
down to 50 km/s, i.e. a velocity dispersion of 20 km/s. Our own software is used for bad-pixel and
cosmic-ray rejection, as well as sky-subtraction and frame shifting and adding39
. Optimal
extraction is applied to the resulting 2D frames, and the one-dimensional spectrum is finally flux
calibrated separately for each arm against the GROND photometry. Spectral binning has no effect
on the steepness of the slope (Extended Data Figure 1). The NIR arm does not contain any useful
signal, as do the two HST grism spectra3
(Extended Data Figure 2).
The observed spectrum is the sum of light from the GRB afterglow, the GRB host galaxy, and the
supernova SN 2011kl. After correcting for AV
Gal
= 0.06 mag Galactic foreground37
extinction, we
corrected for the contribution of the host galaxy using a template fit (§3) on the host photometry
(including the J-band measurement of [3]), and subtracted the afterglow based on the extrapolation
of the g΄r΄i΄z΄ GROND light curves to the time of the X-shooter observation. After conversion to
the rest-frame, we corrected for intrinsic reddening of E(BV)=0.040.01 mag derived from the
GROND afterglow SED fitting (see Extended Data Figure 3 for the effect of each of these steps).
2. Association of GRB afterglow, supernova, and host galaxy
We detect narrow absorption lines of MgII(2796, 2803), MgI(2852) and FeII(2344, 2374,
2382, 2586, 2600) in the SN 2011kl spectrum. No change in equivalent widths and redshift is
11. 11
apparent when compared to the afterglow spectrum3,39
taken 0.75 days after the GRB. Moreover,
these equivalent widths are typical of those seen from host galaxies of bright long-duration GRBs.
This relates the SN to the same host galaxy as GRB 111209A.
No offset is measurable in GROND images between GRB afterglow and supernova (RA<0.''
032,
Decl<0.''
019), which implies that the two events are co-spatial within <200 pc.
3. The host galaxy
During the late-epoch GROND observation the host galaxy is clearly detected in g΄r΄i΄z΄ in the
35 range (last entry in Extended Data Table 1). We add HST F336W and Gemini u'
J from [3].
Noting that the supernova does not contribute significantly any more during these late epochs (with
expected AB magnitudes g'
28.5, r'
28.0, i'
27.5, z'
27.2 mag), we employ LePHARE
40
and use
the best-fit model (a low-mass, star-forming galaxy) as a template for the host subtraction (see
Extended Data Figure 3 and 4). Inferences on the physical properties of the host from this fitting
will be published elsewhere [Kann, D.A. et al. 2015, Astron. Astrophys. (in prep.)] and
absorption/emission line information from the optical/NIR X-shooter spectra are given in [39]. We
note though that the low metal content seen in the SN spectrum is in accord with the very low host
galaxy metallicity (10%-40%), which is somewhat unusual for such a low-redshift object but
commonly seen in SLSN hosts.
4. Radioactivity cannot power the supernova peak
Modelling the bolometric light curve according to the standard scheme of 56
Ni powering41
and
augmented by Co decay42
, an ejecta mass of 3.20.5 M⊙ and a 56
Ni mass of 1.00.1 M⊙ is derived
(we used vph = 20,000 km/s, and a grey opacity of 0.070.01 cm2
g1
, constant in time). The
derived 56
Ni mass is anomalously large for SNeIb/c, including GRB-SNe43
. Such a large 56
Ni
mass is difficult to reconcile with the very low opacity in the blue part of the spectrum. The
continuum flux keeps rising down to 300 nm rest-frame without any sign of suppression implying
very low metal line opacity. Also, the ejected mass of 3 M⊙ as deduced from the light curve
width does not resonate with the large 56
Ni mass.
While it has been suggested that part of the 56
Ni could be synthesised in the accretion disk44
, this is
unlikely to proceed at a rate needed in our case. Recent numerical simulations show that for a wide
range of progenitor masses (13–40 M⊙), initial surface rotational velocities, metallicities and
explosion energies, the required disk mass of more than 1 M⊙ (corresponding to 0.2 M⊙
56
Ni) is
difficult to achieve45
, for both cases of compact objects: (i) in the case of heavy fallback, leading to
the collapse of the central object into a black hole, the explosion energy is required to be small (few
1048
erg), and more importantly, the disk forms only after a few months due to the large fallback
time (~106
s). (ii) in the case of little fallback, leaving a neutron star behind, only fine-tuned
conditions produce fallback disks at all, and these then have lifetimes of at most several hundred
seconds.
Thus, a different mechanism must power the SN light curve during the first 40 days (rest frame).
12. 12
5. Enhanced emission due to interaction with the circumburst medium?
Given the large luminosity, we considered additional emission from the interaction of the
supernova ejecta with the circumstellar medium as an alternative possibility. In that case, one may
expect narrow Balmer emission lines. While we detect very narrow (=35 km/s) H, H and
[OIII] lines in emission, the Balmer fluxes are compatible with the forbidden line flux and with an
origin from the global low (0.02 M⊙/yr) star formation rate in this low-metallicity (10%-40%
solar) host galaxy39
. On the other hand, if the progenitor star was heavily stripped, no circumstellar
H may be present. Another, more serious constraint is the very blue SN spectrum, which would
require a very low density to minimize extinction (though dust may be destroyed by the initial
GRB and SN light). This may be at odds with the requirement that the density is high enough to
generate the few 1043
ergs1
of radiative luminosity observed around the peak.
6. Modelling
We have been able to reproduce the spectrum of SN 2011kl using a radiation transport code18,19
and a density profile where r7
, which is typical of the outer layers of SN explosions. The
spectra appear rather featureless but this does not mean that there is no absorption: the UV is
significantly depressed relative to a blackbody. However, it is much less depressed than the spectra
of GRB-SNe, indicating a lower metal content. Many metal lines are active in the UV (Fe, Co, Ti,
Cr). The smooth appearance of the UV spectrum is the result of the blending of hundreds of lines
caused by the large range of wavelengths over which lines are active (line blanketing). Indeed, the
photospheric velocity (and density) determines the degree of line blending. We used here
photospheric velocities of vph ~ 20,000km/s (grey/black lines in Figure 3), and can see increasingly
featureless spectra as vph increases and lines are active at higher velocities (larger blueshift),
demonstrating the minimum velocity required to broaden unseen absorption around 400 nm
rest-frame (CaII, CII), but at the same time explain the sharp cut-off below 280 nm rest-frame. The
strongest lines that shape this strong blue cut-off are labelled in black (grey ’ISM’ label mark
MgII/FeII absorption lines in the host galaxy). Most of these are blended and do not stand out as
individual features, unlike in classical SLSNe which have vph ~ 10,000 km/s. In the optical, on the
other hand, only few very weak absorption lines are visible in our SN spectrum. These are due to
Ca II and C II lines. O II lines are not detected, and would require large departures from thermal
equilibrium because of the very high ionization/excitation potential of their lower levels (20-30
eV). This suggests the presence of X-rays in SLSNe, probably produced by shocks. Our model
only has 0.4M⊙ of material above the photosphere. The metal content is quite low. It is
consistent with 1/4 of the solar metallicity, which could be the metallicity of the star whose
explosion caused the GRB and the SN, and there is no evidence of freshly synthesised material
mixed-in, unlike in GRB-SNe. This supports the notion that the SN light curve was not powered by
56
Ni decay but rather by a magnetar. Figure 3 shows this model with three different photospheric
velocities overplotted on the X-shooter spectrum.
The spectrum can be reproduced without invoking interaction, but the metal abundance is so low
that it is unlikely that much 56
Ni has been produced. We therefore consider magneto-rotational
energy input as the source of luminosity. Depending on the relative strength of magnetar and
radioactive decay energy deposition, different peak luminosities as well as rise and decay times can
be obtained20
. One particularly pleasant feature of the magnetar mechanism is that it does not
necessarily suffer from strong line blanketing, thus providing a more natural explanation for the
observed spectrum.
13. 13
Using a simple formalism describing rotational energy loss via magnetic dipole radiation and
relating the spin-down rate to the effective radiative diffusion time, one can infer the magnetar’s
initial spin period Pi
and magnetic dipole field strength from the observed luminosity and time to
light curve peak tpeak
. One million combinations of the parameters Pi
, B, Mej
and EK
were sampled
and ranked according to the goodness of fit relative to the data. All best solutions cluster at
P=12.20.3ms and have B=7.51.51014
G, required by the observed short tpeak
(14 rest-frame
days) and the moderate (for a magnetar) peak luminosity. The mass and energy of the ejecta are
less well determined, as they depend on the energy injection by the magnetar, and also due to the
unknown distribution of mass in velocity space below the photosphere. We find a rather low
ejected mass Mej=2.4±0.7 M ⊙ , and energy EK
=(5.53.3)1051
erg. Different photospheric
velocities of e.g. 10,000, 15,000 and 20,000 km/s lead to different ejecta masses of 1.1, 1.7 and 2.2
M⊙, but produce indistinguishable light curves with MNi
=1.00.1 M⊙. Note though that not every
combination of Pi, Mej and EK yields similar results. The GRB energy can be reconciled with the
maximum energy that can be extracted from a magnetar if the correction for collimation of the
GRB jet is a factor of 1/50 or less, which is well within typical values for GRBs22
.
7. Code availability
The code used in [18, 19] is available on request from mazzali@mpa-garching.mpg.de.
8. Supplementary References
[31] Tody, D. IRAF in the nineties. in ASP Conf. 52, Astronomical Data Analysis Software and Systems II,
ed. R.J. Hanisch, R.J.V. Brissenden, & J. Barnes, p. 173 (1993)
[32] Krühler, T. et al. The 2175 Å feature in a gamma-ray burst afterglow at redshift 2.45. Astrophys. J. 685,
376–383 (2008)
[33] Küpcü Yoldaş, A. et al. First results of GROND. AIP Conf. Proc. 1000, 227–231 (2008)
[34] http://www.sdss.org (2013)
[35] www.swift.ac.uk/swift_portal (2014)
[36] Poole, T. S. et al. Photometric calibration of the Swift ultraviolet/optical telescope. Mon. Not. R.
Astron. Soc. 383, 627–645 (2008)
[37] Schlegel, D., Finkbeiner, D., Davis, M. Maps of dust infrared emission for use in estimation of
reddening and cosmic microwave background radiation foregrounds. Astrophys. J 500, 525–553
(1998)
[38] Vernet, J. et al. X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very
Large Telescope. Astron. Astrophys. 536, A105 (2011)
[39] Krühler, T. et al. GRB hosts through cosmic time: An emission-line survey of 95 gamma-ray burst
selected galaxies between 0.1<z<3.6. Astron. Astrophys. (subm.) (2015)
[40] http://www.cfht.hawaii.edu/~
arnouts/LEPHARE (2014)
[41] Arnett, W.D., Type I supernovae. I - Analytic solutions for the early part of the light curve. Astrophys.
J. 253, 785–797 (1982)
[42] Valenti, S. et al. The broad-lined Type Ic supernova 2003jd. Mon. Not. R. Astron. Soc. 383, 1485–
1500 (2008)
[43] Mazzali, P. A., et al. The very energetic, broad-lined Type Ic supernova 2010ah (PTF10bzf) in the
context of GRB/SNe. Mon. Not. R. Astron. Soc. 432, 2463–2473 (2013)
[44] Surman, R., McLaughlin, G.C., Hix, W. R., Nucleosynthesis in the Outflow from Gamma-Ray Burst
Accretion Disks. Astrophys. J. 643, 1057–1064 (2006)
14. 14
[45] Perna, R., Duffell P., Cantiello, M., MacFadyen, A.I., The fate of fallback matter around newly born
compact objects. Astrophys. J. 781, A119 (2014)
[46] Cardelli, J. A., Clayton, G. C., & Mathis, J. S. The relationship between infrared, optical, and
ultraviolet extinction. Astrophys. J. 345, 245–256 (1989)
Extended Data
Extended Data Figure 1 | Binning has no effect on spectral slope.
Original X-shooter spectrum in the UVB (top) and VIS (bottom) arms shown in gray (0.4 Å/pix;
prior to host and afterglow subtraction), with the re-binned (factor 20) spectrum overplotted in
black. The binning does not change the steepness of the spectrum, in particular not at the blue end.
Extended Data Figure 2 | Long-wavelength spectra.
Full X-shooter spectrum near maximum light of SN 2011kl, as well as two HST grism spectra
taken one week before and after the supernova maximum, respectively (both taken from [3].
Above 500 nm rest-frame, none contains any informative absorption lines (all absorption
structures seen are from the Earth atmosphere).
Extended Data Figure 3 | Step-by-step corrections of the supernova spectrum.
Sequence of analysis steps for the X-shooter spectrum, from the only galactic foreground corrected
observed spectrum (top/very light blue), over host subtraction (light blue) and afterglow+host
subtraction (blue). The break at 500 nm observer-frame (300 nm rest-frame) and the steep slope
towards the UV are inherent to the raw spectrum, not a result of afterglow or host subtraction.
Extended Data Figure 4 | Observed spectral energy distribution of the host galaxy of GRB
111209A.
Plotted in blue are GROND g΄r΄i΄z΄ detections (crosses) and GROND JHKS upper limits (triangles)
of the host galaxy of GRB 111209A. Data taken from [3] are F336W (green), Gemini g΄r΄
detections (red crosses) and the J-band upper limit (red triangle). The best-fit LePHARE template
of a low-mass, low-extinction, young star-forming galaxy is shown which is very typical for GRB
host galaxies.
15. 15
Extended Data Table 1 | GROND observations of the afterglow, supernova and host of GRB
111209A.
The t time gives the mid-time of the observation relative to the Swift trigger time. All magnitudes
are in the AB system and not corrected for Galactic foreground extinction. Conversion to Vega
magnitudes: g΄AB - g΄Vega =-0.062 mag, r΄AB - r΄Vega =0.178 mag, i΄AB - i΄Vega =0.410 mag, i΄AB - i΄Vega
=0.543 mag, JAB - JVega =0.929 mag, HAB - HVega =1.394 mag, KS,AB - KS,Vega =1.859 mag.
Corrections for Galactic extinction are Ag
'=0.066 mag, Ar
'=0.046 mag, Ai
'=0.034 mag,
Az
'=0.025 mag, AJ
=0.015 mag, AH
=0.010 mag, AK
S
=0.006 mag.
Extended Data Table 2 | UVOT observations of the afterglow of GRB 111209A.
The t time gives the mid-time of the observation relative to the Swift trigger time, and all
magnitudes are in the AB system and not corrected for Galactic foreground extinction. Conversion
to Vega magnitudes: uAB
uVega
=1.02 mag (as given at
http://swift.gsfc.nasa.gov/analysis/uvot_digest/zeropts.html). The correction for Galactic
extinction, using E(BV)
=0.017 mag 36
and the Galactic extinction curve46
is Au
=0.085 mag.
16. 105
106
107
Seconds after Burst Trigger
26
24
22
20
18
ABmagnitude
1
10
100
FluxDensity(µJy)
10 100
Days after Burst Trigger
r joint fit
r afterglow
r supernova
r host galaxy
u joint fit
u afterglow
u host galaxy
u
g
r
i
z
J