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Related papers: Machine-z: Rapid Machine Learned Redshift Indicato…

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Using Gaussian Mixture Model (GMM) and Expectation Maximization Algorithm, we perform an analysis of time duration ($T_{90}$) for \textit{CGRO}/BATSE, \textit{Swift}/BAT and \textit{Fermi}/GBM Gamma-Ray Bursts. The $T_{90}$ distributions of…

High Energy Astrophysical Phenomena · Physics 2016-08-01 En-Bo Yang , Zhi-Bin Zhang , Chul-Sung Choi , Heon-Young Chang

We present a machine learning (ML) based method for automated detection of Gamma-Ray Burst (GRB) candidate events in the range 60 keV - 250 keV from the AstroSat Cadmium Zinc Telluride Imager data. We use density-based spatial clustering to…

Instrumentation and Methods for Astrophysics · Physics 2021-05-18 Sheelu Abraham , Nikhil Mukund , Ajay Vibhute , Vidushi Sharma , Shabnam Iyyani , Dipankar Bhattacharya , A. R. Rao , Santosh Vadawale , Varun Bhalerao

We present a framework to obtain photometric redshifts (photo-zs) for gamma-ray burst afterglows. Using multi-band photometry from GROND and Swift/UVOT, photo-zs are derived for five GRBs for which spectroscopic redshifts are not available.…

We propose a novel approach, based on Principal Components Analysis, to the use of Gamma-Ray Bursts (GRBs) as probes of cosmic star formation history (SFH) up to very high redshifts. The main advantage of such approach is to avoid the…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-17 Emille E. O. Ishida , Rafael S. de Souza , Andrea Ferrara

We construct the Hubble diagram (HD) of Gamma-Ray Bursts (GRBs) with redshifts reaching up to $z \sim 6$, by using five luminosity vs. luminosity indicator relations calibrated with the Cardassian cosmology. This model has a major…

Astrophysics · Physics 2011-05-24 Herman J. Mosquera Cuesta , Habib Dumet M. , Cristina Furlanetto

Recent evidence appears to link gamma-ray bursts (GRBs) to star-forming regions in galaxies at cosmological distances. If short-lived massive stars are the progenitors of GRBs, the rate of events per unit cosmological volume should be an…

Astrophysics · Physics 2008-11-26 Cristiano Porciani , Piero Madau

Abundances of galaxies at redshifts z > 4 are difficult to obtain from damped Ly {\alpha} (DLA) systems in the sightlines of quasars (QSOs) due to the Ly {\alpha} forest blanketing and the low number of high-redshift quasars detected.…

Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the…

High Energy Astrophysical Phenomena · Physics 2015-06-03 F. Y. Wang , Z. G. Dai , E. W. Liang

Gamma-ray bursts (GRBs) are generally believed to originate from two distinct progenitors, compact binary mergers and massive collapsars. Traditional and some recent machine learning-based classification schemes predominantly rely on…

High Energy Astrophysical Phenomena · Physics 2025-10-22 Si-Yuan Zhu , Lang Shao , Pak-Hin Thomas Tam , Fu-Wen Zhang

Future missions for long gammma-ray burst (GRB) observations at high redshift such as HiZ-GUNDAM and THESEUS will provide clue to the star formation history in our universe. In this paper focusing on high redshift (z>8) GRBs, we calculate…

High Energy Astrophysical Phenomena · Physics 2019-06-26 Tomoya Kinugawa , Yuichi Harikane , Katsuaki Asano

Gamma Ray Bursts (GRBs) visible up to very high redshift have become attractive targets as potential new distance indicators. It is still not clear whether the relations proposed so far originate from an unknown GRB physics or result from…

High Energy Astrophysical Phenomena · Physics 2015-02-24 Maria Giovanna Dainotti , Roberta Del Vecchio , Shigehiro Nagataki , Salvatore Capozziello

Gamma-ray bursts (GRBs) and their afterglows have been proposed as an excellent probe to study the evolution of cosmic star formation, the reionization of the intergalactic medium, and the metal enrichment history of the universe, since the…

We show that the time variability of a gamma-ray burst (GRB) appears to be correlated with the absolute luminosity of the burst: smooth bursts are intrinsically less luminous. This Cepheid-like relationship can be used to determine the…

Astrophysics · Physics 2007-05-23 E. E. Fenimore , E. Ramirez-Ruiz

We show how the redshift and peak-flux distributions of gamma-ray bursts (GRBs) have an observation time dependence that can be used to discriminate between different burst populations. We demonstrate how observation time relations can be…

High Energy Astrophysical Phenomena · Physics 2013-02-20 E. J. Howell , D. M. Coward

The race for the most distant object in the Universe has been played by long-duration gamma-ray bursts (GRBs), star-forming galaxies and quasars. GRBs took a temporary lead with the discovery of GRB 090423 at a redshift z=8.2, but now the…

High Energy Astrophysical Phenomena · Physics 2022-10-19 S. Campana , G. Ghirlanda , R. Salvaterra , O. A. Gonzalez , M. Landoni , G. Pariani , A. Riva5 , M. Riva , S. J. Smartt , N. R. Tanvir , S. D. Vergani

We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of…

Studies of the cosmic gamma-ray bursts (GRBs) and their host galaxies are now starting to provide interesting or even unique new insights in observational cosmology. Observed GRB host galaxies have a median magnitude R ~ 25 mag, and show a…

We compare the properties of optically dark GRBs, defined by the optical-to-X-ray spectral index beta_OX<0.5, and normal ones discovered by the Swift satellite before the year 2008 in a statistical way, using data collected from the…

High Energy Astrophysical Phenomena · Physics 2009-09-24 W. Zheng , J. Deng , J. Wang

It is known that the soft tail of the gamma-ray bursts' spectra show excesses from the exact power-law dependence. In this article we show that this departure can be detected in the peak flux ratios of different BATSE DISCSC energy…

Astrophysics · Physics 2009-11-07 Z. Bagoly , I. Csabai , A. Mészáros , P. Mészáros , I. Horváth , L. G. Balázs , R. Vavrek

Using the near-infrared (NIR) observations of the afterglows of the high redshift ($5 \la z \la 25$) gamma-ray bursts (GRBs) which will be detected by the {\it Swift} satellite, we discuss a way to study the cosmic reionization history. In…

Astrophysics · Physics 2009-11-10 Akio K. Inoue , Ryo Yamazaki , Takashi Nakamura