SpitzerObservations of Gamma‐Ray Burst Host Galaxies: A Unique Window into High‐Redshift Chemical Evolution and Star Formation

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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Ly+ and ultraviolet emission from high-redshift gamma-ray burst hosts: to what extent do gamma-ray bursts trace star formation?

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2005.09289.x ◽

2005 ◽

Vol 362 (1) ◽

pp. 245-251 ◽

Cited By ~ 79

Author(s):

P. Jakobsson ◽

G. Björnsson ◽

J. P. U. Fynbo ◽

G. Jóhannesson ◽

J. Hjorth ◽

...

Keyword(s):

Star Formation ◽

Gamma Ray ◽

High Redshift ◽

Gamma Ray Bursts ◽

Ultraviolet Emission ◽

Gamma Ray Burst

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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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The Host Galaxies of Short GRBs as Probes of Their Progenitor Properties

Galaxies ◽

10.3390/galaxies7010030 ◽

2019 ◽

Vol 7 (1) ◽

pp. 30 ◽

Cited By ~ 1

Author(s):

Massimiliano De Pasquale

Keyword(s):

Star Formation ◽

Gamma Ray ◽

Compact Object ◽

Host Galaxies ◽

Gamma Ray Burst ◽

Star Forming ◽

Be Star ◽

Short Grbs

We present and discuss the properties of host galaxies of short Gamma-ray Burst (SGRBs). In particular, we examine those observations that contribute to the understanding of the progenitor systems of these explosions. Most SGRB hosts are found to be star forming objects, but an important fraction, ∼1/5, of all hosts are elliptical with negligible star formation. Short bursts often occur at very large off-sets from their hosts, in regions where there is little or no underlying host light. Such results have enabled the community to test and improve the models for the production of short GRBs. In particular, the data are in favour of the merger of compact object binaries, provided that the kick velocities from the birth site are a few tens of km/s, and merger times of ∼1 Gyr.

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