New soft batse GRBs and spectra of X-ray rich bursts

Yana Tikhomirova*, Boris Stern, Alexandra Kozyreva, Juri Poutanen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


A population of X-ray dominated gamma-ray bursts (GRBs) observed by Ginga, BeppoSAX and HETE-2 should be represented in the BATSE data as presumably soft bursts. We have performed a search for soft GRBs in the BATSE records in the 25-100 keV energy band. A softness of a burst spectrum can be a reason why it has been missed by the on-board procedure and previous searches for untriggered GRBs tuned to 50-300 keV range. We have found a surprisingly small number (∼20 yr -1 down to 0.1 ph cm -2 s -1) of soft GRBs where the count rate is dominated by 25-50 keV energy channel. This fact as well as the analysis of HETE-2 and common BeppoSAX/BATSE GRBs indicates that the majority of GRBs with a low E peak has a relatively hard tail with the high-energy power-law photon index β > -3. An exponential cutoff in GRB spectra below 20 keV may be a distinguishing feature separating non-GRB events.

Original languageEnglish
Title of host publicationX-ray Universe 2005
Number of pages5
StatePublished - 2006
Externally publishedYes
EventX-ray Universe 2005 - Madrid, Spain
Duration: 26 Sep 200530 Sep 2005

Publication series

NameEuropean Space Agency, (Special Publication) ESA SP
ISSN (Print)0379-6566


ConferenceX-ray Universe 2005


  • Data analysis
  • Gamma-ray bursts


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