Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-25T16:44:39.075Z Has data issue: false hasContentIssue false

Cosmological effects on the observed flux and fluence distributions of gamma-ray bursts

Published online by Cambridge University Press:  05 September 2012

Jakub Řípa
Affiliation:
Institute for the Early Universe, Ewha Womans University, 120-750 Seoul, Korea email: [email protected]; sirrah.troja.mff.cuni.cz
Attila Mészáros
Affiliation:
Astronomical Institute, Charles University, 180 00 Prague, Czech Republic email: [email protected]
Felix Ryde
Affiliation:
Department of Physics, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden email: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Several claims have been put forward that an essential fraction of long-duration BATSE gamma-ray bursts should lie at redshifts larger than 5. This point-of-view follows from the natural assumption that fainter objects should, on average, lie at larger redshifts. However, redshifts larger than 5 are rare for bursts observed by Swift. The purpose of this article is to show that the most distant bursts in general need not be the faintest ones. We derive the cosmological relationships between the observed and emitted quantities, and arrive at a prediction that is tested on the ensembles of BATSE, Swift and Fermi bursts. This analysis is independent on the assumed cosmology, on the observational biases, as well as on any gamma-ray burst model. We arrive to the conclusion that apparently fainter bursts need not, in general, lie at large redshifts. Such a behaviour is possible, when the luminosities (or emitted energies) in a sample of bursts increase more than the dimming of the observed values with redshift. In such a case dP(z)/dz > 0 can hold, where P(z) is either the peak-flux or the fluence. This also means that the hundreds of faint, long-duration BATSE bursts need not lie at high redshifts, and that the observed redshift distribution of long Swift bursts might actually represent the actual distribution.

Type
Poster Papers
Copyright
Copyright © International Astronomical Union 2012

References

Mészáros, A., Řípa, J., & Ryde, F. 2011a, Astronomy & Astrophysics, 529, A55CrossRefGoogle Scholar
Mészáros, A., Řípa, J., & Ryde, F. 2011b, Acta Polytechnica, 51, 45Google Scholar