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A mean redshift of 2.8 for Swift gamma-ray bursts

Jakobsson, P ; Levan, A ; Fynbo, JPU ; Priddey, R ; Hjorth, J ; Tanvir, N ; Watson, D ; Jensen, BL ; Sollerman, J and Natarajan, P , et al. (2006) In Astronomy & Astrophysics 447(3). p.897-903
Abstract
The exceptionally high luminosities of gamma-ray bursts (GRBs), gradually emerging as extremely useful probes of star formation, make them promising tools for exploration of the high-redshift Universe. Here we present a carefully selected sample of Swift GRBs, intended to estimate in an unbiased way the GRB mean redshift (z(mean)), constraints on the fraction of high-redshift bursts and an upper limit on the fraction of heavily obscured afterglows. We find that z(mean) = 2.8 and that at least 7% of GRBs originate at z > 5. In addition, consistent with pre-Swift observations, at most 20% of afterglows can be heavily obscured. The redshift distribution of the sample is qualitatively consistent with models where the GRB rate is... (More)
The exceptionally high luminosities of gamma-ray bursts (GRBs), gradually emerging as extremely useful probes of star formation, make them promising tools for exploration of the high-redshift Universe. Here we present a carefully selected sample of Swift GRBs, intended to estimate in an unbiased way the GRB mean redshift (z(mean)), constraints on the fraction of high-redshift bursts and an upper limit on the fraction of heavily obscured afterglows. We find that z(mean) = 2.8 and that at least 7% of GRBs originate at z > 5. In addition, consistent with pre-Swift observations, at most 20% of afterglows can be heavily obscured. The redshift distribution of the sample is qualitatively consistent with models where the GRB rate is proportional to the star formation rate in the Universe. We also report optical, near-infrared and X-ray observations of the afterglow of GRB 050814, which was seen to exhibit very red optical colours. By modelling its spectral energy distribution we find that z = 5.3 +/- 0.3. The high mean redshift of GRBs and their wide redshift range clearly demonstrates their suitability as efficient probes of galaxies and the intergalactic medium over a significant fraction of the history of the Universe. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
dust, extinction, cosmology : observations, early Universe, galaxies :, gamma rays : bursts, high-redshift
in
Astronomy & Astrophysics
volume
447
issue
3
pages
897 - 903
publisher
EDP Sciences
external identifiers
  • wos:000235777500009
  • scopus:33644524064
ISSN
0004-6361
DOI
10.1051/0004-6361:20054287
language
English
LU publication?
yes
id
f6d1249b-22b7-49d1-aeec-a36a6ad2a0b6 (old id 416957)
date added to LUP
2016-04-01 15:21:59
date last changed
2020-12-08 05:19:45
@article{f6d1249b-22b7-49d1-aeec-a36a6ad2a0b6,
  abstract     = {The exceptionally high luminosities of gamma-ray bursts (GRBs), gradually emerging as extremely useful probes of star formation, make them promising tools for exploration of the high-redshift Universe. Here we present a carefully selected sample of Swift GRBs, intended to estimate in an unbiased way the GRB mean redshift (z(mean)), constraints on the fraction of high-redshift bursts and an upper limit on the fraction of heavily obscured afterglows. We find that z(mean) = 2.8 and that at least 7% of GRBs originate at z > 5. In addition, consistent with pre-Swift observations, at most 20% of afterglows can be heavily obscured. The redshift distribution of the sample is qualitatively consistent with models where the GRB rate is proportional to the star formation rate in the Universe. We also report optical, near-infrared and X-ray observations of the afterglow of GRB 050814, which was seen to exhibit very red optical colours. By modelling its spectral energy distribution we find that z = 5.3 +/- 0.3. The high mean redshift of GRBs and their wide redshift range clearly demonstrates their suitability as efficient probes of galaxies and the intergalactic medium over a significant fraction of the history of the Universe.},
  author       = {Jakobsson, P and Levan, A and Fynbo, JPU and Priddey, R and Hjorth, J and Tanvir, N and Watson, D and Jensen, BL and Sollerman, J and Natarajan, P and Gorosabel, J and Ceron, JMC and Pedersen, K and Pursimo, T and Arnadottir, Anna and Castro-Tirado, AJ and Davis, CJ and Deeg, HJ and Fiuza, DA and Mykolaitis, S and Sousa, SG},
  issn         = {0004-6361},
  language     = {eng},
  number       = {3},
  pages        = {897--903},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {A mean redshift of 2.8 for Swift gamma-ray bursts},
  url          = {http://dx.doi.org/10.1051/0004-6361:20054287},
  doi          = {10.1051/0004-6361:20054287},
  volume       = {447},
  year         = {2006},
}