J/ApJ/820/66 Cosmic evolution of long gamma-ray burst luminosity (Deng+, 2016)
Cosmic evolution of long gamma-ray burst luminosity.
Deng C.-M., Wang X.-G., Guo B.-B., Lu R.-J., Wang Y.-Z., Wei J.-J.,
Wu X.-F., Liang E.-W.
<Astrophys. J., 820, 66 (2016)>
=2016ApJ...820...66D 2016ApJ...820...66D (SIMBAD/NED BibCode)
ADC_Keywords: GRB ; Redshifts ; Spectroscopy
Keywords: gamma-ray burst: general - methods: statistical - stars: formation
Abstract:
The cosmic evolution of gamma-ray burst (GRB) luminosity is essential
for revealing the GRB physics and for using GRBs as cosmological
probes. We investigate the luminosity evolution of long GRBs with a
large sample of 258 Swift/BAT GRBs. By describing the peak luminosity
evolution of individual GRBs as Lp∝(1+z)k, we get k=1.49±0.19
using the nonparametric τ statistics method without considering
observational biases of GRB trigger and redshift measurement. By
modeling these biases with the observed peak flux and characterizing
the peak luminosity function of long GRBs as a smoothly broken power
law with a break that evolves as Lb∝(1+z)kb, we obtain
kb=1.14+0.99-0.47 through simulations based on the assumption
that the long GRB rate follows the star formation rate incorporating
the cosmic metallicity history. The derived k and kb values are
systematically smaller than those reported in previous papers. By
removing the observational biases of the GRB trigger and redshift
measurement based on our simulation analysis, we generate mock
complete samples of 258 and 1000 GRBs to examine how these biases
affect the τ statistics method. We get k=0.94±0.14 and k=0.80±0.09
for the two samples, indicating that these observational biases may
lead to overestimating the k value. With the large uncertainty of kb
derived from our simulation analysis, one cannot even convincingly
argue for a robust evolution feature of the GRB luminosity.
Description:
Our sample includes only the redshift-known long GRBs observed with
Swift/BAT from 2005 January to 2015 April. Low-luminosity GRBs are
excluded since they may belong to another distinct population (e.g.,
Chapman et al. 2007MNRAS.382L..21C 2007MNRAS.382L..21C; Liang et al. 2007ApJ...662.1111L 2007ApJ...662.1111L;
Lu et al. 2010ApJ...725.1965L 2010ApJ...725.1965L). Although the durations of some GRBs,
such as GRB 050724 and GRB 060614, are larger than 2s, we do not include
them in our sample since they may be from merger of compact stars
(Berger et al. 2005Natur.438..988B 2005Natur.438..988B; Gehrels et al. 2006Natur.444.1044G 2006Natur.444.1044G;
Zhang et al. 2007ApJ...655L..25Z 2007ApJ...655L..25Z, 2009ApJ...703.1696Z 2009ApJ...703.1696Z). The afterglow
and host galaxy observations of the high-z SGRB GRB 090426
(T90=1.2s) show that it may be from the collapse of a massive star
(Antonelli et al. 2009A&A...507L..45A 2009A&A...507L..45A; Xin et al. 2011MNRAS.410...27X 2011MNRAS.410...27X).
We thus include this GRB in our sample. We finally obtain a sample of
258 GRBs. They are reported in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 258 The Data of Our GRB Sample
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See also:
J/ApJS/175/179 : The BAT1 gamma-ray burst catalog (Sakamoto+, 2008)
J/ApJ/711/495 : Durations of Swift/BAT GRBs (Butler+, 2010)
J/ApJ/731/103 : Redshift catalog for Swift long GRBs (Xiao+, 2011)
J/ApJS/195/2 : The second Swift BAT GRB catalog (BAT2) (Sakamoto+, 2011)
(Lien+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB GRB name (YYMMDDA)
9- 15 F7.5 --- z Redshift (1)
17- 21 F5.2 [10-7W] log10Lp The 1s peak isotropic luminosity in
the 15-150keV band, log10Lp (in erg/s)
23- 26 F4.2 [10-7W] e_log10Lp Uncertainty in log10Lp
28- 33 F6.2 ph/cm2/s P The 1s peak photon flux in the 15-150keV band
(in photons/cm2/s) (1)
35- 38 F4.2 ph/cm2/s e_P Uncertainty in P (1)
40- 43 F4.2 --- Gamma Photon index Γ (1) (2)
45- 48 F4.2 --- e_Gamma Uncertainty in Gamma (1)
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Note (1): Data taken from the NASA Web site (http://swift.gsfc.nasa.gov/).
Note (2): All of the 1s peak spectra of bursts are fitted to a simple power
law, giving a photon index Γ.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 06-Feb-2018