scholarly journals The luminosity function and formation rate of a complete sample of long gamma-ray bursts

2019 ◽  
Vol 488 (4) ◽  
pp. 4607-4613 ◽  
Author(s):  
Guang-Xuan Lan ◽  
Hou-Dun Zeng ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Likelihood Method ◽  
Complete Sample ◽  
Empirical Density ◽  
Power Law Function ◽  
Current Sample ◽  
First Time

ABSTRACT We study the luminosity function and formation rate of long gamma-ray bursts (GRBs) by using a maximum likelihood method. This is the first time this method is applied to a well-defined sample of GRBs that is complete in redshift. The sample is composed of 99 bursts detected by the Swift satellite, 81 of them with measured redshift and luminosity for a completeness level of $82\, {\rm per\, cent}$. We confirm that a strong redshift evolution in luminosity (with an evolution index of $\delta =2.22^{+0.32}_{-0.31}$) or in density ($\delta =1.92^{+0.20}_{-0.21}$) is needed in order to reproduce the observations well. But since the predicted redshift and luminosity distributions in the two scenarios are very similar, it is difficult to distinguish between these two kinds of evolutions only on the basis of the current sample. Furthermore, we also consider an empirical density case in which the GRB rate density is directly described as a broken power-law function and the luminosity function is taken to be non-evolving. In this case, we find that the GRB formation rate rises like $(1+z)^{3.85^{+0.48}_{-0.45}}$ for $z\lesssim 2$ and is proportional to $(1+z)^{-1.07^{+0.98}_{-1.12}}$ for $z\gtrsim 2$. The local GRB rate is $1.49^{+0.63}_{-0.64}$ Gpc−3 yr−1. The GRB rate may be consistent with the cosmic star formation rate (SFR) at $z\lesssim 2$, but shows an enhancement compared to the SFR at $z\gtrsim 2$.

scholarly journals Formation Rate, Evolving Luminosity Function, Jet Structure, and Progenitors for Long Gamma‐Ray Bursts

2004 ◽  
Vol 611 (2) ◽  
pp. 1033-1040 ◽  
Author(s):  
Claudio Firmani ◽  
Vladimir Avila‐Reese ◽  
Gabriele Ghisellini ◽  
Alexander V. Tutukov
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Jet Structure

The isotropic energy function and formation rate of short gamma-ray bursts

2021 ◽  
Vol 21 (10) ◽  
pp. 254
Author(s):  
Zhi-Ying Liu ◽  
Fu-Wen Zhang ◽  
Si-Yuan Zhu
Keyword(s):  
Energy Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Local Formation ◽  
Isotropic Energy ◽  
Energy Functions ◽  
Cosmic Evolution ◽  
First Time ◽  
The Universe

Abstract Gamma-ray bursts (GRBs) are brief, intense, gamma-ray flashes in the universe, lasting from a few milliseconds to a few thousand seconds. For short gamma-ray bursts (sGRBs) with duration less than 2 seconds, the isotropic energy (E iso) function may be more scientifically meaningful and accurately measured than the luminosity (L p) function. In this work we construct, for the first time, the isotropic energy function of sGRBs and estimate their formation rate. First, we derive the L p – E p correlation using 22 sGRBs with known redshifts and well-measured spectra and estimate the pseduo redshifts of 334 Fermi sGRBs. Then, we adopt the Lynden-Bell c − method to study isotropic energy functions and formation rate of sGRBs without any assumption. A strong evolution of isotropic energy E iso ∝ (1+z)5.79 is found, which is comparable to that between L p and z. After removing effect of the cosmic evolution, the isotropic energy function can be reasonably fitted by a broken power law, which is ϕ ( E iso , 0 ) ∝ E iso , 0 − 0.45 for dim sGRBs and ϕ ( E iso , 0 ) ∝ E iso , 0 − 1.11 for bright sGRBs, with the break energy 4.92 × 1049 erg. We obtain the local formation rate of sGRBs is about 17.43 events Gpc−3 yr−1. If assuming a beaming angle is 6° to 26°, the local formation rate including off-axis sGRBs is estimated as ρ 0,all = 155.79 – 3202.35 events Gpc−3 yr−1.

scholarly journals A complete sample of long bright Swift gamma ray bursts

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120235 ◽  
Author(s):  
Gianpiero Tagliaferri ◽  
Ruben Salvaterra ◽  
Sergio Campana ◽  
Stefano Covino ◽  
Paolo D’Avanzo ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Cosmic Time ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Complete Sample ◽  
Peak Flux ◽  
S Peak ◽  
Prompt Emission

Complete samples are the basis of any population study. To this end, we selected a complete subsample of Swift long bright gamma ray bursts (GRBs). The sample, made up of 58 bursts, was selected by considering bursts with favourable observing conditions for ground-based follow-up observations and with the 15–150 keV 1 s peak flux above a flux threshold of 2.6 photons cm −2  s −1 . This sample has a redshift completeness level higher than 90 per cent. Using this complete sample, we investigate the properties of long GRBs and their evolution with cosmic time, focusing in particular on the GRB luminosity function, the prompt emission spectral-energy correlations and the nature of dark bursts.

scholarly journals Are LGRBs biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of LGRBs

2015 ◽  
Vol 11 (A29B) ◽  
pp. 249-250
Author(s):  
Susanna D. Vergani ◽  
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Star Formation Rate ◽  
Massive Stars ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
Complete Sample ◽  
Rate Versus ◽  
High Metallicity

AbstractLong gamma-ray bursts (LGRBs) are associated to the deaths of massive stars and could thus be used as a potentially powerful tool to trace cosmic star formation. However the conditions needed to produce a LGRBs may introduce a bias in the LGRB rate versus star formation rate (SFR) relation (called LGRB efficiency hereafter).We have undertaken a study of the properties of the host galaxies of the BAT6 complete sample of LGRB to improve our knowledge on the LGRB efficiency, its redshift evolution, and the factor affecting it. This is the base to properly use LGRBs as SFR tracers.We show that at z < 1 LGRBs are not direct SFR tracers because they tend to avoid high-metallicity galaxies. The use of the BAT6 complete sample keeps this result from being affected by possible biases that could have influenced past results based on incomplete samples. The preference for low (but not extremely low) metallicities can be a consequence of the particular conditions needed for the progenitor star to produce a GRB.

scholarly journals A COMPLETE SAMPLE OF BRIGHTSWIFTLONG GAMMA-RAY BURSTS. I. SAMPLE PRESENTATION, LUMINOSITY FUNCTION AND EVOLUTION

2012 ◽  
Vol 749 (1) ◽  
pp. 68 ◽  
Author(s):  
R. Salvaterra ◽  
S. Campana ◽  
S. D. Vergani ◽  
S. Covino ◽  
P. D’Avanzo ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Complete Sample ◽  
Sample Presentation

scholarly journals The Luminosity Function of Long Gamma-Ray Burst and their rate at z ≥ 6

2008 ◽  
Vol 4 (S255) ◽  
pp. 212-216
Author(s):  
R. Salvaterra ◽  
S. Campana ◽  
G. Chincarini ◽  
T. R. Choudhury ◽  
S. Covino ◽  
...  
Keyword(s):  
Star Formation ◽  
Luminosity Function ◽  
Gamma Ray ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Test Model ◽  
The Past ◽  
Model Predictions ◽  
Low Metallicity ◽  
Luminosity Evolution

AbstractWe compute the luminosity function (LF) and the formation rate of long gamma ray bursts (GRBs) in three different scenarios: i) GRBs follow the cosmic star formation and their LF is constant in time; ii) GRBs follow the cosmic star formation but the LF varies with redshift; iii) GRBs form preferentially in low–metallicity environments. We then test model predictions against the Swift 3-year data, showing that scenario i) is robustly ruled out. Moreover, we show that the number of bright GRBs detected by Swift suggests that GRBs should have experienced some sort of luminosity evolution with redshift, being more luminous in the past. Finally we propose to use the observations of the afterglow spectrum of GRBs at z ≥ 5.5 to constrain the reionization history, and then applied our method to the case of GRB 050904.

The X-ray luminosity function of short gamma-ray bursts

2021 ◽  
Vol 366 (4) ◽  
Author(s):  
Zhi-Ying Liu ◽  
Fu-Wen Zhang ◽  
Si-Yuan Zhu
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
X Ray
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