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

Conference · Mon Sep 01 04:00:00 EDT 1997

OSTI ID:645553

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

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1. National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
2. Los Alamos National Lab., NM (United States)
3. ISAS, Sagamihara, Kanagawa (Japan)
4. RIKEN, Wako, Saitama (Japan)

The authors summarize the spectral characteristics of a sample of 22 bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2--400 keV range, providing a unique opportunity to characterize the largely unexplored X-ray properties of gamma-ray bursts. The photon spectra of the 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 Compton Observatory. However, below 20 keV they find evidence for a positive spectral number index in approximately 40% of their burst sample, with some evidence for a strong rolloff at lower energies in a few events. They 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 their sample is 24%.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Management and Administration, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 645553
• Report Number(s): LA-UR--97-4393; CONF-9709153--; ON: DE98002923
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COSMIC GAMMA BURSTS
KEV RANGE
PROPORTIONAL COUNTERS
SATELLITES
SCINTILLATION COUNTERS
X-RAY SPECTRA