The luminosity function and the rate of Swift's gamma-ray bursts

David Wanderman*, Tsvi Piran

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

327 Scopus citations

Abstract

We invert directly the redshift-luminosity distribution of observed long Swift gamma-ray bursts (GRBs) to obtain their rate and luminosity function. Our best-fitting rate is described by a broken power law that rises like for 0 < z < 3 and decreases like for z > 3. The local rate is ρ0 ≃ 1.3+0.6-0.7 (Gpc-3 yr-1). The luminosity function is well described by a broken power law with a break at L* ≃ 1052.5±0.2 (erg s-1) and with indices α = 0.2+0.2-0.1 and β = 1.4+0.3-0.6. The recently detected GRB 090423, with z ≈ 8, fits nicely into the model's prediction, verifying that we are allowed to extend our results to high redshifts. While the GRB rate may follow the star formation rate (SFR) for z < 3, the high-redshift slope is shallower than the steep decline in the SFR for 4 < z. However, we cannot rule out a GRB rate that follows one of the recent SFR models.

Original languageEnglish
Pages (from-to)1944-1958
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume406
Issue number3
DOIs
StatePublished - Aug 2010

Keywords

  • Gamma-ray burst: general
  • Stars: formation

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