X-ray flashes in ROSAT PSPC data

Conference · Tue Dec 01 04:00:00 EST 1998

OSTI ID:291110

Sun, X; Li, H; Fenimore, E E ^[1]; Wang, Q D ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Northwestern Univ., Evanston, IL (United States)

The authors find 24 short (200--2,500s) X-ray flashes from all the ROSAT Position Sensitive Proportional Counter (PSPC) observations above galactic latitude 30 degrees ({approximately} 9.6 Msec) and some observations toward low latitudes ({approximately} 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 {ge} 2.4 keV, or by a single power-law with the photon number index of {approx} {minus}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, they could not statistically establish that there are two different populations between nearby galaxies and control fields.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: National Aeronautics and Space Administration, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 291110
• Report Number(s): LA-UR--98-307; CONF-9709153--; ON: DE99000633
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COSMIC GAMMA BURSTS
COSMIC RAY DETECTION
COSMIC X-RAY BURSTS
COSMIC X-RAY SOURCES
DATA ANALYSIS
GALAXIES
X RADIATION