GRB redshifts & host galaxies: An unbiased sample

P. Jakobsson*, D. Malesani, J. P.U. Fynbo, J. Hjorth, B. Milvang-Jensen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


We describe the current status and recent results from (1) our ongoing programmes at various telescopes, including the VLT and NOT, aimed at performing target-of-opportunity follow-up spectroscopy of gamma-ray burst (GRB) afterglows; (2) our Swift/VLT legacy survey, a VLT Large Programme aimed at characterizing the host galaxies of a homogeneously selected sub-sample of Swift GRBs. The primary goal of (1) is to secure redshifts for a complete sample of GRBs: The redshift completion is now 52% with z̄ = 2.26. However, the observed GRB redshift distribution is still too uncertain to infer conclusively about the mapping from star-formation rate to GRB rate. The immediate goals of (2) is to determine the host luminosity function, study the effects of reddening, determine the fraction of Lyα emitters in the hosts, and obtain redshifts for targets with no absorption redshift. The main effort so far has been the definition of a very carefully selected sample, obeying strict and well-defined selection criteria: 71 targets in total. Among the preliminary results is a large optical detection rate, the lack of extremely red objects (only one possible case in the sample) and an update of the GRB redshift distribution with z̄ ∼2.0.

Original languageEnglish
Title of host publicationGamma-Ray Burst - 6th Huntsville Symposium
Number of pages9
Publication statusPublished - 2009
Event6th Huntsville Symposium on Gamma-Ray Bursts - Huntsville, AL, United States
Duration: 20 Oct 200823 Oct 2008

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference6th Huntsville Symposium on Gamma-Ray Bursts
Country/TerritoryUnited States
CityHuntsville, AL

Other keywords

  • γ-ray bursts -
  • Dust
  • Early universe -
  • Extinction
  • Galaxies: high redshift -


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