X-ray spectral properties of {gamma}-ray bursts

Journal Article · Fri May 01 04:00:00 EDT 1998 · AIP Conference Proceedings

OSTI ID:641446

Strohmayer, T E ^[1]; Fenimore, E E ^[2]; Murakami, T ^[3]; Yoshida, A ^[4]

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1. LHEA, NASA/GSFC, Greenbelt, Maryland 20771 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
3. ISAS, 1-1 Yoshinodai 3, Sagamihara, Kanagawa, 229 (Japan)
4. RIKEN, 2-1, Hirowawa, Wako, Saitama, 351-01 (Japan)

We summarize the spectral characteristics of a sample of 22 bright {gamma}-ray bursts detected with the {gamma}-ray burst sensors aboard the satellite {ital Ginga}. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2{endash}400 keV range, providing a unique opportunity to characterize the largely unexplored X-ray properties of {gamma}-ray bursts. The photon spectra of the {ital Ginga} bursts are well described by a low-energy slope, a bend energy, and a high-energy slope. In the energy range where they can be compared, this result is consistent with burst spectral analyses obtained from the BATSE experiment aboard the {ital Compton Observatory}. However, below 20 keV we find evidence for a positive spectral number index in approximately 40{percent} of our burst sample, with some evidence for a strong rolloff at lower energies in a few events. We find that the distribution of spectral bend energies extends below 10 keV. The observed ratio of energy emitted in the X-rays relative to the {gamma}-rays can be much larger than a few percent and, in fact, is sometimes larger than unity. The average for our sample is 24{percent}. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 641446
• Report Number(s): CONF-9709153--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 428; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COSMIC GAMMA BURSTS
COSMIC PHOTONS
COSMIC X-RAY SOURCES
PHOTODETECTORS
SPECTRAL DENSITY
X-RAY SPECTRA