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GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z=0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the…

To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000 gamma-ray bursts (GRBs), of which ~ 360 GRBs have redshift measurements, ranging from z = 0.03 to z = 9.38. We present the analyses of the BAT-detected GRBs for the…

We present a catalog of the redshift estimates and probability distributions for 1366 individual Long-duration Gamma-Ray Bursts (LGRBs) detected by the Burst And Transient Source Experiment (BATSE). This result is based on a careful…

High Energy Astrophysical Phenomena · Physics 2019-03-19 Amir Shahmoradi , Robert J. Nemiroff

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…

High Energy Astrophysical Phenomena · Physics 2013-10-17 Wei-Wei Tan , Xiao-Feng Cao , Yun-Wei Yu

Until 6 October 2005 sixteen redshifts have been measured of long gamma-ray bursts discovered by the Swift satellite. Further 45 redshifts have been measured of the long gamma-ray bursts discovered by other satellites. Here we perform five…

The delay in the arrival times between high and low energy photons from cosmic sources can be used to test the violation of the Lorentz invariance (LIV), predicted by some quantum gravity theories, and to constrain its characteristic energy…

High Energy Astrophysical Phenomena · Physics 2017-11-29 M. G. Bernardini , G. Ghirlanda , S. Campana , P. D'Avanzo , J. -L. Atteia , S. Covino , G. Ghisellini , A. Melandri , F. Piron , R. Salvaterra , G. Tagliaferri

The lack of bright host galaxies in several recently examined gamma-ray burst (GRB) error boxes suggests that the redshifts of cosmological GRBs may be significantly higher than previously believed. On the other hand, the non-detection of…

Astrophysics · Physics 2009-10-30 Daniel E. Holz , M. Coleman Miller , Jean M. Quashnock

Using a novel approach, the distribution of fluences of long gamma ray bursts derived from the Swift-BAT catalog, was reproduced by a jet-model characterized by the distribution of the total radiated energy in $\gamma$-rays and the…

High Energy Astrophysical Phenomena · Physics 2013-11-18 Chadia Kanaan , Jose A. de Freitas Pacheco

The accumulation of {\it Swift} observed gamma-ray bursts (GRBs) gradually makes it possible to directly derive a GRB luminosity function (LF) from observational luminosity distribution, where however two complexities must be involved as…

High Energy Astrophysical Phenomena · Physics 2012-07-11 Xiao-Feng Cao , Yun-Wei Yu , K. S. Cheng , Xiao-Ping Zheng

Some short gamma-ray bursts (SGRBs) exhibit a short duration and spectral hard emission (referred to as a "hard spike") followed by a slightly longer soft emission (known as a "soft tail"). We identified nine SGRBs with known redshift in…

High Energy Astrophysical Phenomena · Physics 2024-04-04 Naoki Ogino , Daisuke Yonetoku , Makoto Arimoto , Tatsuya Sawano , Hamid Hamidani

Starting from the Swift sample we define a complete sub-sample of 58 bright long Gamma Ray Bursts (GRB), 55 of them (95%) with a redshift determination, in order to characterize their properties. Our sample (BAT6) allows us to study the…

High Energy Astrophysical Phenomena · Physics 2013-09-11 R. Salvaterra , S. Campana , S. Covino , P. D'Avanzo , G. Ghirlanda , G. Ghisellini , A. Melandi , G. Tagliaferri , L. Nava , S. Vergani

We employ realistic constraints on selection effects to model the Gamma-Ray Burst (GRB) redshift distribution using {\it Swift} triggered redshift samples acquired from optical afterglows and the TOUGH survey. Models for the Malmquist bias,…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-16 David Coward , Eric Howell , Marica Branchesi , Bruce Gendre , Giulia Stratta

The instantaneous emission from a relativistic surface endowed with a Lorentz factor $\Gamma$ that decreases away from the outflow symmetry axis can naturally explain the three phases observed by Swift/XRT in GRBs and their afterglows (GRB…

High Energy Astrophysical Phenomena · Physics 2025-05-13 A. Panaitescu

We remark on the utility of an observational relation between the absorption column density in excess of the Galactic absorption column density, $\Delta N_{\rm H} = N_{\rm H, fit} - N_{\rm H, gal}$, and redshift, z, determined from all 55…

To draw inferences about gamma-ray burst (GRB) source populations based on Swift observations, it is essential to understand the detection efficiency of the Swift burst alert telescope (BAT). This study considers the problem of modeling the…

High Energy Astrophysical Phenomena · Physics 2016-02-10 Philip B Graff , Amy Y Lien , John G Baker , Takanori Sakamoto

Recent astrophysical transient Swift J1913.1+1946 may be associated with the $\gamma$-ray burst GRB 221009A. The redshift of this event is $z\simeq 0.151$. Very high-energy $\gamma$-rays (up to 18 TeV) followed the transient and were…

High Energy Physics - Phenomenology · Physics 2023-05-23 Shyam Balaji , Maura E. Ramirez-Quezada , Joseph Silk , Yongchao Zhang

Swift/BAT has detected ~ 200 long-duration GRBs, with redshift measurements for ~50 of them. We derive the luminosity function (Phi^{HL}) and the local event rate (rho_0^{HL}) of the conventional high luminosity (HL) GRBs by using the…

Astrophysics · Physics 2011-02-11 Enwei Liang , Bing Zhang , Francisco Virgili , Z. G. Dai

The lag-luminosity relation for gamma-ray bursts (GRBs) is an anti-correlation between the time lag, tau_lag, which represents the delay between the arrival of hard and soft photons, and the isotropic peak luminosity, L. In this paper, we…

High Energy Astrophysical Phenomena · Physics 2012-03-30 Walid J. Azzam

(Abridged). We present a sample of 77 optical afterglows (OAs) of Swift detected GRBs for which spectroscopic follow-up observations have been secured. We provide linelists and equivalent widths for all detected lines redward of Ly-alpha.…