Modeling the ISM Properties of Metal-Poor Galaxies and Gamma-Ray Burst Hosts

AbstractRecent research has suggested that long-duration gamma-ray bursts (LGRBs) occur preferentially in low-metallicity environments, but the exact nature of this correlation is currently a matter of intense debate. We use the newest generation of the Starburst99/Mappings code to generate an extensive suite of cutting-edge stellar population synthesis models, covering a wide range of physical parameters specifically tailored for modeling the ISM environments of metal-poor galaxies and LGRB host galaxies. With our models, we generate optical emission line diagnostics, which will allow us to examine the ISM properties and stellar populations of a variety of galaxy populations in unprecedented detail. While accurately modeling low-metallicity galaxies still poses a challenge to these models, future improvements to these grids will have profound consequences for our understanding of metal-poor galaxies, their ISM environments, and the nature of their role as the hosts of LGRBs.

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The Optical Emission from Gamma-Ray Quasars

Publications of the Astronomical Society of Australia ◽

10.1071/as01123 ◽

2003 ◽

Vol 20 (2) ◽

pp. 196-202 ◽

Cited By ~ 4

Author(s):

M. T. Whiting ◽

P. Majewski ◽

R. L. Webster

Keyword(s):

Near Infrared ◽

Gamma Ray ◽

Optical Emission ◽

Accretion Disc ◽

Photometric Observations ◽

Wide Range

AbstractWe present photometric observations of six radio-loud quasars that were detected by the COMPTEL gamma-ray telescope. The data encompass seven wavebands in the optical and near infrared. After correction for Galactic extinction, we find a wide range in optical slopes. Two sources are as blue as optically-selected quasars, and are likely to be dominated by the accretion disc emission, while three others show colours consistent with a red synchrotron component. We discuss the properties of the COMPTEL sample of quasars, as well as the implications our observations have for multiwavelength modelling of gamma-ray quasars.

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No supernovae detected in two long-duration gamma-ray bursts

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2006.1994 ◽

2007 ◽

Vol 365 (1854) ◽

pp. 1269-1275 ◽

Cited By ~ 8

Author(s):

D Watson ◽

J.P.U Fynbo ◽

C.C Thöne ◽

J Sollerman

Keyword(s):

Massive Star ◽

Gamma Ray ◽

Compact Star ◽

Gamma Ray Bursts ◽

Host Galaxy ◽

Core Collapse ◽

Host Galaxies ◽

Star Forming ◽

Long Duration ◽

Spiral Arm

There is strong evidence that long-duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies the GRB. This association has been confirmed in observations of several nearby GRBs. Recent observations show that some long-duration GRBs are different. No SN emission accompanied the long-duration GRBs 060505 and 060614 down to limits fainter than any known Type Ic SN and hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration. Furthermore, the bursts originated in star-forming galaxies, and in the case of GRB 060505, the burst was localized to a compact star-forming knot in a spiral arm of its host galaxy. We find that the properties of the host galaxies, the long duration of the bursts and, in the case of GRB 060505, the location of the burst within its host, all imply a massive stellar origin. The absence of an SN to such deep limits therefore suggests a new phenomenological type of massive stellar death.

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A Possible Detection of CO (J = 3–2) Emission From the Host Galaxy of GRB 980425 with Atacama Submillimeter Telescope Experiment

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306006776 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 312-312

Author(s):

Bunyo Hatsukade ◽

Kotaro Kohno ◽

Akira Endo ◽

Tomoka Tosaki ◽

Kouji Ohta ◽

...

Keyword(s):

Star Formation ◽

Gamma Ray ◽

Line Emission ◽

Emission Feature ◽

Star Formation History ◽

Host Galaxy ◽

Host Galaxies ◽

Long Duration ◽

The Galaxy ◽

Multi Wavelength

AbstractLong-duration gamma-ray bursts (GRBs) are considered to be due to the death of massive stars. Therefore, GRBs are closely associated with the star formation of host galaxies. Since GRBs can be detected at cosmological distances, they are expected to be probes of the star formation history of the Universe. In order to determine the use of GRBs, it is essential to understand the star formation of their hosts. Multi-wavelength observations have shown that the star formation rates (SFRs) of GRB hosts derived from submillimeter/radio observations are generally higher than those from optical/UV observations (Berger et al. 2003). This implies that GRB hosts have a large amount of molecular gas and massive star formation obscured by dust. In order to solve this problem, it is necessary to derive the SFRs in a method which is independent of existing methods and not affected by dust extinction.We observed 12CO (J = 3–2) line emission from the host galaxy of GRB 980425 using the Atacama Submillimeter Telescope Experiment (ASTE). Five points were observed covering the entire region of the galaxy, and we find possible emission features (S/N ~ 3 σ) at the velocity range corresponding to the redshift of the galaxy. By combining all spectra of five points, we obtain a global spectrum with a ~4 σ emission feature. If the features are real, this is the first detection of CO among GRB hosts. We derive the total gas mass of M(H2)=7 ± 2× 108M⊙ assuming a CO-to-H2 conversion factor of αCO = 8.0M⊙ (K km s−1 pc2)−1, which is deduced using the correlation between the αCO and the metallicity. The dynamical mass is calculated to be Mdyn=2× 1010M⊙, and M(H2)/Mdyn~3% is consistent with those of nearby dwarfs and normal spirals. The derived SFR is 0.5 ± 0.1 M⊙ yr−1 based on the Schmidt law. This SFR agrees with the results of previous Hα observations, suggesting that there is no significant obscured star formation in this host galaxy. This result implies that there is a variety of GRB hosts in terms of the presence of obscured star formation.

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Inflow of atomic gas fuelling star formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316005056 ◽

2015 ◽

Vol 11 (A29B) ◽

pp. 229-230

Author(s):

M. J. Michałowski ◽

G. Gentile ◽

J. Hjorth ◽

M. R. Krumholz ◽

N. R. Tanvir ◽

...

Keyword(s):

Star Formation ◽

Gamma Ray ◽

Molecular Gas ◽

Host Galaxies ◽

Gas Reservoirs ◽

Gamma Ray Burst ◽

Gas Cooling ◽

Low Metallicity ◽

Atomic Gas ◽

Compact Array

AbstractGamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation in these galaxies may be fuelled by recent inflow of metal-poor atomic gas. While this process is debated, it can happen in low-metallicity gas near the onset of star formation because gas cooling (necessary for star formation) is faster than the Hi-to-H2 conversion.

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Can we quickly flag ultra-long gamma-ray bursts?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1036 ◽

2019 ◽

Vol 486 (2) ◽

pp. 2471-2476 ◽

Cited By ~ 4

Author(s):

B Gendre ◽

Q T Joyce ◽

N B Orange ◽

G Stratta ◽

J L Atteia ◽

...

Keyword(s):

Gamma Ray ◽

High Energy ◽

Gamma Ray Bursts ◽

Wide Field ◽

Exact Nature ◽

X Ray ◽

Central Engine ◽

Long Duration ◽

Limited Coverage

Abstract Ultra-long gamma-ray bursts are a class of high-energy transients lasting several hours. Their exact nature is still elusive, and several models have been proposed to explain them. Because of the limited coverage of wide-field gamma-ray detectors, the study of their prompt phase with sensitive narrow-field X-ray instruments could help in understanding the origin of ultra-long GRBs. However, the observers face a true problem in rapidly activating follow-up observations, due to the challenging identification of an ultra-long GRB before the end of the prompt phase. We present here a comparison of the prompt properties available after a few tens of minutes of a sample of ultra-long GRBs and normal long GRBs, looking for prior indicators of the long duration. We find that there is no such clear prior indicator of the duration of the burst. We also found that statistically, a burst lasting at least 10 and 20 minutes has respectively $28{{\ \rm per\ cent}}$ and $50{{\ \rm per\ cent}}$ probability to be an ultralong event. These findings point towards a common central engine for normal long and ultra-long GRBs, with the collapsar model privileged.

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GAMMA-RAY BURSTS — OBSERVATIONS

International Journal of Modern Physics D ◽

10.1142/s021827181001710x ◽

2010 ◽

Vol 19 (06) ◽

pp. 977-984

Author(s):

N. GEHRELS ◽

J. K. CANNIZZO

Keyword(s):

Gamma Ray ◽

Optical Emission ◽

High Energy ◽

Gamma Ray Bursts ◽

Medium Energy ◽

Host Galaxies ◽

Data Set ◽

Spectral Signatures ◽

High Energy Emission ◽

Combined Data

We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high-energy emission.

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Revisiting Metallicity of Long Gamma-Ray Burst Host Galaxies: The Role of Chemical Inhomogeneities in Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312013397 ◽

2011 ◽

Vol 7 (S279) ◽

pp. 369-370

Author(s):

Yuu Niino

Keyword(s):

Gamma Ray ◽

Gamma Ray Bursts ◽

Necessary Condition ◽

Theoretical Studies ◽

Host Galaxies ◽

Cast Doubt ◽

Low Metallicity ◽

High Metallicity ◽

Metallicity Distribution

AbstractSome theoretical studies on the origin of long gamma-ray bursts (GRBs) using stellar evolution models suggest that a low metallicity environment may be a necessary condition for a GRB to occur. However, recent discoveries of high-metallicity host galaxies of some GRBs cast doubt on the requirement of low-metallicity in GRB occurrence. In this study, we predict the metallicity distribution of GRB host galaxies, assuming empirical formulations of galaxy properties. We take internal dispersion of metallicity within each galaxy into account. Assuming GRBs trace low-metallicity star formation 12+log(O/H) < 8.2, we find that ≳ 10% of GRB host galaxies may have Z > Z⊙, depending on the internal dispersion of metallicity within galaxies.

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A Search for Early Optical Emission from Short- and Long-Duration Gamma-Ray Bursts

The Astrophysical Journal ◽

10.1086/321719 ◽

2001 ◽

Vol 554 (2) ◽

pp. L159-L162 ◽

Cited By ~ 38

Author(s):

Robert Kehoe ◽

Carl Akerlof ◽

Richard Balsano ◽

Scott Barthelmy ◽

Jeff Bloch ◽

...

Keyword(s):

Gamma Ray ◽

Optical Emission ◽

Gamma Ray Bursts ◽

Long Duration

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Simulating High-Redshift Disk Galaxies: Applications to Long Duration Gamma-Ray Burst Hosts

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308027361 ◽

2008 ◽

Vol 4 (S254) ◽

pp. 35-40

Author(s):

Brant E. Robertson

Keyword(s):

Star Formation ◽

Molecular Hydrogen ◽

Gamma Ray ◽

High Redshift ◽

Disk Galaxies ◽

Host Galaxies ◽

Long Duration ◽

Low Mass ◽

Hydrodynamical Simulations ◽

The Impact

AbstractThe efficiency of star formation governs many observable properties of the cosmological galaxy population, yet many current models of galaxy formation largely ignore the important physics of star formation and the interstellar medium (ISM). Using hydrodynamical simulations of disk galaxies that include a treatment of the molecular ISM and star formation in molecular clouds (Robertson & Kravtsov 2008), we study the influence of star formation efficiency and molecular hydrogen abundance on the properties of high-redshift galaxy populations. In this work, we focus on a model of low-mass, star forming galaxies at 1 ≲ z ≲ 2 that may host long duration gamma-ray bursts (GRBs). Observations of GRB hosts have revealed a population of faint systems with star formation properties that often differ from Lyman-break galaxies (LBGs) and more luminous high-redshift field galaxies. Observed GRB sightlines are deficient in molecular hydrogen, but it is unclear to what degree this deficiency owes to intrinsic properties of the galaxy or the impact the GRB has on its environment. We find that hydrodynamical simulations of low-stellar mass systems at high-redshifts can reproduce the observed star formation rates and efficiencies of GRB host galaxies at redshifts 1 ≲ z ≲ 2. We show that the compact structure of low-mass high-redshift GRB hosts may lead to a molecular ISM fraction of a few tenths, well above that observed in individual GRB sightlines. However, the star formation rates of observed GRB host galaxies imply molecular gas masses of 108 – 109M⊙ similar to those produced in the simulations, and may therefore imply fairly large average H2 fractions in their ISM.

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