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Title: A DISTINCT PEAK-FLUX DISTRIBUTION OF THE THIRD CLASS OF GAMMA-RAY BURSTS: A POSSIBLE SIGNATURE OF X-RAY FLASHES?

Abstract

Gamma-ray bursts (GRBs) are the most luminous events in the universe. Going beyond the short-long classification scheme, we work in the context of three burst populations with the third group of intermediate duration and softest spectrum. We are looking for physical properties which discriminate the intermediate duration bursts from the other two classes. We use maximum likelihood fits to establish group memberships in the duration-hardness plane. To confirm these results we also use k-means and hierarchical clustering. We use Monte Carlo simulations to test the significance of the existence of the intermediate group and we find it with 99.8% probability. The intermediate duration population has a significantly lower peak flux (with 99.94% significance). Also, long bursts with measured redshift have higher peak fluxes (with 98.6% significance) than long bursts without measured redshifts. As the third group is the softest, we argue that we have related them with X-ray flashes among the GRBs. We give a new, probabilistic definition for this class of events.

Authors:
;  [1];  [2];  [3]
  1. Department of Physics of Complex Systems, Eoetvoes University, Pazmany P. s. 1/A, H-1117 Budapest (Hungary)
  2. Department of Physics, Bolyai Military University, P.O. Box 15, H-1581 Budapest (Hungary)
  3. Charles University, Faculty of Mathematics and Physics, Astronomical Institute, V Holesovickach 2, 180 00 Prague 8 (Czech Republic)
Publication Date:
OSTI Identifier:
21476654
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 725; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/725/2/1955; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPUTERIZED SIMULATION; COSMIC GAMMA BURSTS; MAXIMUM-LIKELIHOOD FIT; MONTE CARLO METHOD; PROBABILISTIC ESTIMATION; PROBABILITY; RED SHIFT; UNIVERSE; X RADIATION; CALCULATION METHODS; COSMIC RADIATION; ELECTROMAGNETIC RADIATION; IONIZING RADIATIONS; MATHEMATICAL SOLUTIONS; NUMERICAL SOLUTION; PRIMARY COSMIC RADIATION; RADIATIONS; SIMULATION

Citation Formats

Veres, P, Bagoly, Z, Horvath, I, Meszaros, A, and Balazs, L. G., E-mail: veresp@elte.h. A DISTINCT PEAK-FLUX DISTRIBUTION OF THE THIRD CLASS OF GAMMA-RAY BURSTS: A POSSIBLE SIGNATURE OF X-RAY FLASHES?. United States: N. p., 2010. Web. doi:10.1088/0004-637X/725/2/1955.
Veres, P, Bagoly, Z, Horvath, I, Meszaros, A, & Balazs, L. G., E-mail: veresp@elte.h. A DISTINCT PEAK-FLUX DISTRIBUTION OF THE THIRD CLASS OF GAMMA-RAY BURSTS: A POSSIBLE SIGNATURE OF X-RAY FLASHES?. United States. https://doi.org/10.1088/0004-637X/725/2/1955
Veres, P, Bagoly, Z, Horvath, I, Meszaros, A, and Balazs, L. G., E-mail: veresp@elte.h. 2010. "A DISTINCT PEAK-FLUX DISTRIBUTION OF THE THIRD CLASS OF GAMMA-RAY BURSTS: A POSSIBLE SIGNATURE OF X-RAY FLASHES?". United States. https://doi.org/10.1088/0004-637X/725/2/1955.
@article{osti_21476654,
title = {A DISTINCT PEAK-FLUX DISTRIBUTION OF THE THIRD CLASS OF GAMMA-RAY BURSTS: A POSSIBLE SIGNATURE OF X-RAY FLASHES?},
author = {Veres, P and Bagoly, Z and Horvath, I and Meszaros, A and Balazs, L. G., E-mail: veresp@elte.h},
abstractNote = {Gamma-ray bursts (GRBs) are the most luminous events in the universe. Going beyond the short-long classification scheme, we work in the context of three burst populations with the third group of intermediate duration and softest spectrum. We are looking for physical properties which discriminate the intermediate duration bursts from the other two classes. We use maximum likelihood fits to establish group memberships in the duration-hardness plane. To confirm these results we also use k-means and hierarchical clustering. We use Monte Carlo simulations to test the significance of the existence of the intermediate group and we find it with 99.8% probability. The intermediate duration population has a significantly lower peak flux (with 99.94% significance). Also, long bursts with measured redshift have higher peak fluxes (with 98.6% significance) than long bursts without measured redshifts. As the third group is the softest, we argue that we have related them with X-ray flashes among the GRBs. We give a new, probabilistic definition for this class of events.},
doi = {10.1088/0004-637X/725/2/1955},
url = {https://www.osti.gov/biblio/21476654}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 725,
place = {United States},
year = {Mon Dec 20 00:00:00 EST 2010},
month = {Mon Dec 20 00:00:00 EST 2010}
}