ROSAT Observations of the May 1 1992 Gamma Ray Burst Source

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Session 10 -- Gamma Ray Sources
Display presentation, Monday, 30, 1994, 9:20-6:30

[10.03] ROSAT Observations of the May 1 1992 Gamma Ray Burst Source

M. Sommer (MPE), K. Hurley, P. Li (UC Berkeley SSL), C. Kouveliotou, G.J. Fishman (MSFC), M. Boer, M. Niel (CESR), J. Laros (U. Arizona), T. Cline (NASA/GSFC)

The gamma-ray burst of May 1 1992 was observed and rapidly localized by the 3rd Interplanetary Network, and a 2000 s ROSAT TOO observation was carried out on the small error box. A weak x-ray source was detected, but with too few photons to determine the spectral and temporal characteristics of the source. We have recently carried out a 30 ksec PSPC observation of this source, resulting in the detection of 140 photons. We find that the spectrum is consistent with thermal bremsstrahlung from a 7 million degree plasma with about $10^{22} cm^{-2}$ column depth. In addition, analysis of the photon arrival times indicates that the source is variable. The distance implied by the column depth makes it unlikely that this source is coronal emission from a field star. Optical and HRI observations of this region are now planned or underway. We discuss the possible identification of this object and its implication for the GRB source.

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