相关论文: Redshifts of the Long Gamma-Ray Bursts

Due to their highly luminous nature, gamma-ray bursts (GRBs) are useful tools in studying the early Universe (up to z = 10). We consider whether the available subset of Swift high redshift GRBs are unusual when compared to analogous…

We exploit the 14 gamma-ray bursts (GRBs) with known redshifts $z$ and the 7 GRBs for which there are constraints on $z$ to determine the GRB rate $R_{\rm GRB}(z)$, using a method based on Bayesian inference. We find that, despite the…

We predict the redshift distribution of long Gamma-Ray Bursts (GRBs) with Monte Carlo simulations. Our improved analysis constrains free parameters with three kinds of observation: (i) the log(N)-log(P) diagram of BATSE bursts; (ii) the…

The majority of Swift gamma-ray bursts (GRBs) observed at z > 6 have prompt durations of T90 < 30s, which, at first sight, is surprising given that cosmological time-dilation means this corresponds to < 5s in their rest frames. We have…

We compare the burst distribution of the new (2B) BATSE catalogue to a cosmological distribution. The observed distribution agrees well with a cosmological one, however, it is insensitive to cosmological parameters such as $\O$ and…

In order to reveal possible non-homogeneities in the spatial distribution of long (T_90 > 2^s) gamma-ray bursts we have examined 201 of them with known redshifts z. For different functional forms of metric distance r(z)we use the…

In this work, we restudy the dependence of luminosity function and event rates for different gamma-ray burst samples on the criteria of sample selection and threshold effect. To compare with many previous studies, we have chosen two samples…

We exploit the 14 gamma-ray bursts (GRBs) with known redshifts z and the 7 GRBs for which there are constraints on z to determine the GRB rate R_{GRB}(z), using a method based on Bayesian inference. We find that, despite the qualitative…

In this letter, we calculate the redshift distribution of gamma-ray bursts assuming that they trace (i) the globally averaged star formation rate or (ii) the average metallicity in the Universe. While at redshifts 5 and below, both the star…

We study statistically 197 long gamma-ray bursts, detected and measured in detail by the BATSE instrument of the Compton Gamma-Ray Observatory. In the sample 10 variables, describing for any burst the time behavior of the spectra and other…

GRBs are now detected up to z = 8.26 . We try to find differences, in their restframe properties, which could be related either to distance or to observing conditions.

Although starburst galaxies have relatively flat spectral energy distributions, their strong optical emission lines and near-UV continua make it very feasible to estimate their redshifts photometrically. In this work, I describe a…

It was found by Amati et al. in 2002 that for a small sample of 9 gamma-ray bursts, more distant events appear to be systematically harder in the soft gamma-ray band. Here, we have collected a larger sample of 65 gamma-ray bursts, whose…

We present results of a calculation of absorption of 10-500 GeV gamma-rays at high redshifts. This calculation requires the determination of the high- redshift evolution of the full spectral energy distribution of the intergalactic photon…

The recent discovery that faint gamma-ray bursts are stretched in time relative to bright ones has been interpreted as support for cosmological distances: faint bursts have their durations redshifted relative to bright ones. It was pointed…

The determination of luminosity function (LF) of gamma-ray bursts (GRBs) is of an important role for the cosmological applications of the GRBs, which is however hindered seriously by some selection effects due to redshift measurements. In…

One of the most important task of the Gamma-Ray Burst field is the classification of the bursts. Many researches have proven the existence of the third kind (intermediate duration) of GRBs in the BATSE data. Recent works have analyzed…

The distance scale to gamma ray bursts has been a subject of scientific debate for almost thirty years. Up to the discovery of afterglows only indirect methods could be used to constrain the distance scale to this objects. I review some of…

We show that if the intrinsic break energy of Gamma-Ray Bursts (GRBs) is determined by the product of more than three random variables the observed break energy distribution becomes almost lognormal including the redshift effect because of…

We present the results of the spectral analysis of a sample of short bright $\gamma$--ray bursts (GRB) detected by BATSE and compare them with the average and time resolved spectral properties of long bright bursts. While the spectral…