X-ray flashes in ROSAT PSPC data

Journal Article · Fri May 01 04:00:00 EDT 1998 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.55469· OSTI ID:641445

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

---

1. NIS-2, MS D436, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Northwestern University, 2131 Sheridan Road, Evanston, Illinois 60208 (United States)

We find 24 short (200{endash}2500s) 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 {gt}200 in less than 100 sec. Its spectrum can be fitted either by a thermal plasma model with kT{ge}2.7thinspkeV, 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, we could not statistically establish that there are two different populations between nearby galaxies and control fields. {copyright} {ital 1998 American Institute of Physics.}

• Sponsoring Organization: USDOE
• OSTI ID: 641445
• Report Number(s): CONF-9709153--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 428; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COSMIC GAMMA BURSTS
COSMIC X-RAY BURSTS
COSMIC X-RAY SOURCES
GALAXIES
SPECTRAL DENSITY
STELLAR FLARES
X-RAY SPECTRA