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We discuss three classes of x-ray transients to highlight three new types of transients found with the Wide Field Cameras onboard BeppoSAX. First there are the transients related to Low Mass X-ray Binaries in outburst, typically lasting…

Astrophysics · Physics 2007-05-23 John Heise , Jean in 't Zand

We report evidence from the 3B Catalogue that long ($T_{90} > 10$ s) and short ($T_{90} < 10$ s) gamma-ray bursts represent distinct source populations. Their spatial distributions are significantly different, with long bursts having…

Astrophysics · Physics 2009-10-28 J. I. Katz , L. M. Canel

Gamma-ray bursts (GRBs) are believed to belong to two classes and they are conventionally divided according to their durations. This classification scheme is not satisfied due to the fact that duration distributions of the two classes are…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Yi-Ping Qin , Zhi-Fu Chen

A sample of 427 gamma-ray bursts (GRBs), measured by the RHESSI satellite, is studied statistically with respect to duration and hardness ratio. Standard statistical tests are used, such as $\chi^2$, F-test and the maximum likelihood ratio…

High Energy Astrophysical Phenomena · Physics 2015-05-13 J. Řípa , A. Mészáros , C. Wigger , D. Huja , R. Hudec , W. Hajdas

We present X-ray light curves (1.5-12 keV) for fifteen gamma-ray bursts (GRBs) detected by the All-Sky Monitor on the Rossi X-ray Timing Explorer. We compare these soft X-ray light curves with count rate histories obtained by the…

We have searched for ultra-long (> 100 s) gamma-ray transients in the data from the anticoincidence shield (ACS) of the SPI gamma-ray spectrometer onboard the INTEGRAL orbital observatory and classified them by machine learning methods. We…

It was recently shown that the $T_{90}-H_{32}$ distributions of gamma-ray bursts from CGRO/BATSE and Fermi/GBM are well described by a mixture of only two skewed components, making the presumed third, intermediate class unnecesary. The…

High Energy Astrophysical Phenomena · Physics 2020-03-03 Mariusz Tarnopolski

We present a comprehensive statistical analysis of Swift X-ray light-curves of Gamma-Ray Bursts (GRBs), with more than 650 GRBs. Two questions drive this effort: (1) Does the X-ray emission retain any kind of memory of the prompt phase? (2)…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Raffaella Margutti , E. Zaninoni , M. G. Bernardini , G. Chincarini

We argue that the distributions of both the intrinsic fluence and the intrinsic duration of the gamma-ray emission in gamma-ray bursts from the BATSE sample are well represented by log-normal distributions, in which the intrinsic dispersion…

Astrophysics · Physics 2011-05-23 L. G. Balazs , Z. Bagoly , I. Horvath , A. Meszaros , P. Meszaros

The automatic classification of X-ray detections is a necessary step in extracting astrophysical information from compiled catalogs of astrophysical sources. Classification is useful for the study of individual objects, statistics for…

Instrumentation and Methods for Astrophysics · Physics 2024-01-30 Víctor Samuel Pérez-Díaz , Juan Rafael Martínez-Galarza , Alexander Caicedo , Raffaele D'Abrusco

Gamma-ray bursts (GRBs) rank among the most powerful astrophysical phenomena, characterized by complex and highly variable prompt emission light curves that reflect the dynamics of their central engines. In this work, we analyze a sample of…

High Energy Astrophysical Phenomena · Physics 2026-01-28 Ruo-Yu Guan , Fei-Fei Wang , Yuan-Chuan Zou

The duration of a gamma-ray burst (GRB) is a key indicator of its physics origin, with long bursts perhaps associated with the collapse of massive stars and short bursts with mergers of neutron stars.However, there is substantial overlap in…

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

A sample of 286 gamma-ray bursts (GRBs) detected by the Swift satellite and 358 GRBs detected by the RHESSI satellite are studied statistically. Previously published articles, based on the BATSE GRB Catalog, claimed the existence of an…

High Energy Astrophysical Phenomena · Physics 2015-05-14 J. Ripa , D. Huja , A. Meszaros , R. Hudec , W. Hajdas , C. Wigger

We investigate spectral evolution in 37 bright, long gamma-ray bursts observed with the BATSE Spectroscopy Detectors. High resolution spectra are characterized by the energy of the peak of \nfn~and the evolution of this quantity is examined…

A wavelet analysis has been performed on 80 intense gamma-ray bursts GRBs) from the BATSE 3B catalog with durations longer than 2 seconds. The wavelet analysis applied novel features developed for edge detection in image processing and this…

Astrophysics · Physics 2010-12-13 Kevin J. Hurley , Brian McBreen , Fergus Quilligan , Matt Delaney , Lorraine Hanlon

We investigated the main prompt and afterglow emission parameters of gamma-ray bursts detected by the Burst Alert Telescope (BAT) and X-Ray Telescope installed on the Swift satellite. Our aim was to look for differences or connections…

High Energy Astrophysical Phenomena · Physics 2013-09-05 J. Kóbori , Z. Bagoly , L. G. Balázs , I. Horváth

Cluster analysis is a widely applied machine learning technique to understand the existing patterns in the population of gamma-ray bursts (GRBs), in order to explore their physical sources. In the present scenario, the number of clusters…

High Energy Astrophysical Phenomena · Physics 2026-05-29 Soumita Modak

Traditionally gamma-ray bursts (GRBs) are classified in the $T_{90}$-hardness ratio two-dimensional plane into long/soft and short/hard GRBs. In this paper, we suggest to add the "amplitude" of GRB prompt emission as the third dimension as…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hou-Jun Lü , Bing Zhang , En-Wei Liang , Bin-Bin Zhang , Takanori Sakamoto

In this paper we give a brief review of our recent studies on the long and short gamma-ray bursts (GRBs) detected Swift, in an effort to understand the puzzle of classifying GRBs. We consider that it is still an appealing conjecture that…

High Energy Astrophysical Phenomena · Physics 2014-01-29 Lang Shao , Fu-Wen Zhang , Zi-Gao Dai , Zhi-Ping Jin , Jing-Zhi Yan , Da-Ming Wei
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