X-ray flashes in ROSAT PSPC data
Abstract
We find 24 short (200-2500s) X-ray flashes from all the ROSAT Position Sensitive Proportional Counter (PSPC) observations above galactic latitude 30 degrees (~9.6 Msec) and some observations toward low latitudes (~2.4 Msec). The brightest flash is quite extraordinary. Its flux rises from nondetection by a factor of >200 in less than 100 sec. Its spectrum can be fitted either by a thermal plasma model with kT>=2.7 keV, or by a single power-law with the photon number index of ~-1.7. Photon statistics are not sufficient to obtain spectra for other flashes. The flash event fields can vary from optically crowded regions to blank fields. Although eight flashes are found from observations from nearby galaxies, and three of them are within the optical extent of their corresponding galaxies, we could not statistically establish that there are two different populations between nearby galaxies and control fields.
- Publication:
-
Gamma-Ray Bursts, 4th Hunstville Symposium
- Pub Date:
- May 1998
- DOI:
- 10.1063/1.55469
- Bibcode:
- 1998AIPC..428..456S
- Keywords:
-
- 98.70.Qy;
- 95.85.Nv;
- X-ray sources;
- X-ray bursts;
- X-ray