| Autor: |
M. Niel, L. P. Moskaleva, V. S. Dolidze, E. Jourdain, R. Kucherova, A. M. Chernenko, J-L. Atteia, Yu. A. Surkov, Alexei Pozanenko, A. Vilchinskaya, G. Vedrenne, N. Khavenson, O. Scheglov, I. G. Mitrofanov, S. Khariukova, A.V. Dyachkov, C. Barat, A. A. Kozlenkov |
| Rok vydání: |
1991 |
| Předmět: |
|
| Zdroj: |
Planetary and Space Science. 39:23-37 |
| ISSN: |
0032-0633 |
| DOI: |
10.1016/0032-0633(91)90122-q |
| Popis: |
The Soviet-French experiment APEX (Barat et al ., 1989. Instruments and Methods far Space Studies (Edited by Balebanov, V. M.), pp. 213–218) was designed to record cosmic gamma-ray transients in the 64 keV–9.2 MeV energy range. Between July 1988 and February 1989 about 80 cosmic gamma-ray bursts (GRBs) were detected, of which 50 were sufficiently strong to allow a study of their fine time/energy structure. This paper reviews the first results obtained at the time of the Phobos meeting, its goal is to point out interesting features appearing in the APEX data for 13 bursts. A detailed analysis of these observations is now under way, and results will be published in the near future. Although GRB time histories generally involve series of peaks with characteristic durations of several seconds, rich multi-pulse time structures on timescales down to several milliseconds are often observed within pulses. With a time resolution of several tens of milliseconds we have obtained evidence for fast spectral evolution ; various spectral components are found to vary on this scale. The observations show the previously known (Mazets et al ., 1981. Nature 290 , 378) absorption-like features below 100 keV as well as spectral features (either broad or line-like) in the range 200–1200 keV. A general conclusion is drawn that both multi-pulse time histories and multi-component energy spectra reflect the complex time/energy behaviour of cosmic GRBs. The observations could be explained by the superposition of variable elementary sources radiating gamma-rays in the vicinity of a neutron star. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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