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

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.

scholarly journals Are LGRBs biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of LGRBs

2015 ◽  
Vol 11 (A29B) ◽  
pp. 249-250
Author(s):  
Susanna D. Vergani ◽  
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Star Formation Rate ◽  
Massive Stars ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
Complete Sample ◽  
Rate Versus ◽  
High Metallicity

AbstractLong gamma-ray bursts (LGRBs) are associated to the deaths of massive stars and could thus be used as a potentially powerful tool to trace cosmic star formation. However the conditions needed to produce a LGRBs may introduce a bias in the LGRB rate versus star formation rate (SFR) relation (called LGRB efficiency hereafter).We have undertaken a study of the properties of the host galaxies of the BAT6 complete sample of LGRB to improve our knowledge on the LGRB efficiency, its redshift evolution, and the factor affecting it. This is the base to properly use LGRBs as SFR tracers.We show that at z < 1 LGRBs are not direct SFR tracers because they tend to avoid high-metallicity galaxies. The use of the BAT6 complete sample keeps this result from being affected by possible biases that could have influenced past results based on incomplete samples. The preference for low (but not extremely low) metallicities can be a consequence of the particular conditions needed for the progenitor star to produce a GRB.

High-Metallicity Host Galaxies and The Metallicity Dependence of Long Gamma-Ray Bursts

2011 ◽  
Author(s):  
Yuu Niino ◽  
J. E. McEnery ◽  
J. L. Racusin ◽  
N. Gehrels
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
High Metallicity

scholarly journals One star, two stars, or both? Investigating metallicity-dependent models for gamma-ray burst progenitors with the IllustrisTNG simulation

2020 ◽  
Vol 495 (1) ◽  
pp. 266-277 ◽  
Author(s):  
Benjamin Metha ◽  
Michele Trenti
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Formation Rate ◽  
Current Data ◽  
Host Galaxy ◽  
Best Fitting ◽  
Low Metallicity ◽  
Stellar Masses ◽  
High Metallicity ◽  
Metallicity Distribution

ABSTRACT The rate of long-duration gamma-ray bursts (GRBs) has been identified as a potential proxy for the star formation rate (SFR) across redshift, but the exact relationship depends on GRB progenitor models (single versus binary). The single-progenitor collapsar model accounts for the preference towards low-metallicity GRB progenitors, but is in apparent tension with some high-metallicity GRB host galaxy measurements. As a possible solution, we consider the scenario where high-metallicity GRB hosts harbour low-metallicity regions in which GRB progenitors form. For this, we use the IllustrisTNG cosmological hydrodynamical simulation to investigate the internal metallicity distribution of GRB hosts, implementing in post-processing different GRB formation models. Predictions (GRB rate, host metallicities, and stellar masses) are compared to the high-completeness GRB legacy surveys BAT6 and SHOALS and a sample of high-redshift GRB-DLA metallicities, allowing us to compute their relative likelihoods. When the internal metallicity distribution of galaxies is ignored, the best-fitting model requires a metallicity-independent channel, as previously proposed by Trenti, Perna, & Jimenez. However, when the internal metallicity distribution is considered, a basic metallicity bias model with a cutoff at $Z_{\rm max}=0.35\, \mathrm{\it Z}_\odot$ is the best-fitting one. Current data are insufficient to discriminate among more realistic metallicity bias models, such as weak metallicity dependence of massive binaries versus stronger metallicity bias of collapsars. An increased sample of objects, and direct measurements of host stellar masses at redshift z &gt; 2 would allow to further constrain the origin of long GRBs.

scholarly journals Star Formation and the Metallicity Aversion of Long-Duration Gamma-Ray Bursts

2011 ◽  
Vol 7 (S279) ◽  
pp. 232-236
Author(s):  
John F. Graham ◽  
Andrew S. Fruchter
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Type Ii ◽  
Local Type ◽  
Search Volume ◽  
Long Duration ◽  
Low Metallicity ◽  
Very High ◽  
Metallicity Distribution

AbstractIt has been suggested that the apparent bias of long-duration GRBs (LGRBs) to low metallicity environments might be a result of the fact that star-formation is anti-correlated with metallicity. However, if this were the cause, one would expect other indicators of star formation, such as Type II and Type Ic SNe to demonstrate a similar bias. Here we show that local Type Ic and Type II SNe track the star-formation weighted metallicity distribution of the SDSS galaxies. In contrast LGRBs are typically found at far-lower metallicities than would be expected based on the distribution of star-formation. This is true even when one takes into account so-called “dark bursts”. Indeed, while we will present data that show that some LGRBs form at very high metallicities, these objects enter the sample because of the large effective search volume produced by their bright hosts. The bias of LGRBs to low metallicity is real and must be related to a mechanism which is crucial in their formation.

scholarly journals Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs

2019 ◽  
Vol 623 ◽  
pp. A26 ◽  
Author(s):  
J. T. Palmerio ◽  
S. D. Vergani ◽  
R. Salvaterra ◽  
R. L. Sanders ◽  
J. Japelj ◽  
...  
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
High Mass ◽  
Close Binary ◽  
Host Galaxies ◽  
Star Forming ◽  
High Metallicity

Aims. Long gamma-ray bursts (LGRB) have been proposed as promising tracers of star formation owing to their association with the core-collapse of massive stars. Nonetheless, previous studies we carried out at z <  1 support the hypothesis that the conditions necessary for the progenitor star to produce an LGRB (e.g. low metallicity), were challenging the use of LGRBs as star-formation tracers, at least at low redshift. The goal of this work is to characterise the population of host galaxies of LGRBs at 1 < z < 2, investigate the conditions in which LGRBs form at these redshifts and assess their use as tracers of star formation. Methods. We performed a spectro-photometric analysis to determine the stellar mass, star formation rate, specific star formation rate and metallicity of the complete, unbiased host galaxy sample of the Swift/BAT6 LGRB sample at 1 < z < 2. We compared the distribution of these properties to the ones of typical star-forming galaxies from the MOSDEF and COSMOS2015 Ultra Deep surveys, within the same redshift range. Results. We find that, similarly to z <  1, LGRBs do not directly trace star formation at 1 < z < 2, and they tend to avoid high-mass, high-metallicity host galaxies. We also find evidence for an enhanced fraction of starbursts among the LGRB host sample with respect to the star-forming population of galaxies. Nonetheless we demonstrate that the driving factor ruling the LGRB efficiency is metallicity. The LGRB host distributions can be reconciled with the ones expected from galaxy surveys by imposing a metallicity upper limit of logOH ∼ 8.55. We can determine upper limits on the fraction of super-solar metallicity LGRB host galaxies of ∼20%, 10% at z <  1, 1 <  z <  2, respectively. Conclusions. Metallicity rules the LGRB production efficiency, which is stifled at Z ≳ 0.7 Z⊙. Under this hypothesis we can expect LGRBs to trace star formation at z >  3, once the bulk of the star forming galaxy population are characterised by metallicities below this limit. The role played by metallicity can be explained by the conditions necessary for the progenitor star to produce an LGRB. The moderately high metallicity threshold found is in agreement with the conditions necessary to rapidly produce a fast-rotating Wolf-Rayet stars in close binary systems, and could be accommodated by single star models under chemically homogeneous mixing with very rapid rotation and weak magnetic coupling.

scholarly journals ROLE OF THE 3.6M DOT TO INVESTIGATE CONNECTIONS BETWEEN LONG-GRBS AND CORE-COLLAPSE SNE

2021 ◽  
Vol 53 ◽  
pp. 127-133
Author(s):  
A. Kumar ◽  
S. B. Pandey ◽  
R. Gupta ◽  
A. Aryan ◽  
A. J. Castro-Tirado ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Global Network ◽  
Core Collapse ◽  
Robotic Telescopes ◽  
The Time Domain ◽  
Time Critical ◽  
Near Future

Newly installed 3.6m DOT at Nainital (Uttarakhand) is a novel facility for the time domain astronomy. Because of the longitudinal advantage of India, it could be used to study new transients reported by a global network of robotic telescopes. Observations with the 4K × 4K CCD Imager at the axial port of the 3.6m DOT will be very helpful in the near future towards understanding the different physical aspects of time-critical events, e.g., Gamma-ray bursts (GRBs), Supernovae, Gravitational wave candidates, etc. Using the Imager with broadband filters (Bessel UBVRI and SDSS ugriz), ~6.5' × 6.5' images could be obtained to attempt various science goals in synergy with other multi-band facilities. In this study, we present an analysis of unpublished R-band data of GRB 171205A/SN 2017iuk spanning between ~12 to 105 days since burst, that observed using the 3.6m DOT with 4K × 4K CCD Imager. In the R-band light curve, a bump appears to start from ~3 days, which shows the peak at ~15 days after the burst, clearly indicates photometric evidence of association of SN with GRB 171205A.

scholarly journals The Redshift Dependence of the Radio Flux of Gamma-Ray Bursts and Their Host Galaxies

2018 ◽  
Vol 865 (2) ◽  
pp. 82 ◽  
Author(s):  
Z. B. Zhang ◽  
P. Chandra ◽  
Y. F. Huang ◽  
D. Li
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Radio Flux ◽  
Host Galaxies

scholarly journals Constraints on the circumburst environments of short gamma-ray bursts

2020 ◽  
Vol 495 (4) ◽  
pp. 4782-4799 ◽  
Author(s):  
Brendan O’Connor ◽  
Paz Beniamini ◽  
Chryssa Kouveliotou
Keyword(s):  
Gamma Ray ◽  
Galactic Halo ◽  
Gamma Ray Bursts ◽  
Light Curves ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Binary Neutron Star ◽  
Range Of Values ◽  
Short Grbs

ABSTRACT Observational follow up of well localized short gamma-ray bursts (SGRBs) has left $20\!-\!30{{\ \rm per\ cent}}$ of the population without a coincident host galaxy association to deep optical and NIR limits (≳26 mag). These SGRBs have been classified as observationally hostless due to their lack of strong host associations. It has been argued that these hostless SGRBs could be an indication of the large distances traversed by the binary neutron star system (due to natal kicks) between its formation and its merger (leading to an SGRB). The distances of GRBs from their host galaxies can be indirectly probed by the surrounding circumburst densities. We show that a lower limit on those densities can be obtained from early afterglow light curves. We find that ${\lesssim}16{{\ \rm per\ cent}}$ of short GRBs in our sample took place at densities ≲10−4 cm−3. These densities represent the expected range of values at distances greater than the host galaxy’s virial radii. We find that out of the five SGRBs in our sample that have been found to be observationally hostless, none are consistent with having occurred beyond the virial radius of their birth galaxies. This implies one of two scenarios. Either these observationally hostless SGRBs occurred outside of the half-light radius of their host galaxy, but well within the galactic halo, or in host galaxies at moderate to high redshifts (z ≳ 2) that were missed by follow-up observations.

scholarly journals The Observed Offset Distribution of Gamma-Ray Bursts from Their Host Galaxies: A Robust Clue to the Nature of the Progenitors

2002 ◽  
Vol 123 (3) ◽  
pp. 1111-1148 ◽  
Author(s):  
J. S. Bloom ◽  
S. R. Kulkarni ◽  
S. G. Djorgovski
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies
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