A distinct peak-flux distribution of the third class of gamma-ray bursts: A possible signature of X-ray flashes?

P. Veres, Z. Bagoly, I. Horváth, A. Mészáros, L. Balázs

Research output: Contribution to journalArticle

37 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)1955-1964
Number of pages10
JournalAstrophysical Journal
Volume725
Issue number2
DOIs
Publication statusPublished - Dec 20 2010

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gamma ray bursts
hardness
flash
bursts
physical property
signatures
simulation
x rays
universe
physical properties
test
distribution

Keywords

  • Gamma rays:general
  • Methods:statistical

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics
  • Nuclear and High Energy Physics

Cite this

A distinct peak-flux distribution of the third class of gamma-ray bursts : A possible signature of X-ray flashes? / Veres, P.; Bagoly, Z.; Horváth, I.; Mészáros, A.; Balázs, L.

In: Astrophysical Journal, Vol. 725, No. 2, 20.12.2010, p. 1955-1964.

Research output: Contribution to journalArticle

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AU - Balázs, L.

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