THE ROSAT XRT SKY SURVEY OF X-RAY SOURCES IN GLOBULAR-CLUSTERS

Citation
F. Verbunt et al., THE ROSAT XRT SKY SURVEY OF X-RAY SOURCES IN GLOBULAR-CLUSTERS, Astronomy and astrophysics, 300(3), 1995, pp. 732-745
Citations number
54
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046361
Volume
300
Issue
3
Year of publication
1995
Pages
732 - 745
Database
ISI
SICI code
0004-6361(1995)300:3<732:TRXSSO>2.0.ZU;2-E
Abstract
We present data obtained on globular dusters during the Rosat XRT + PS PC Sky Survey. Sources were detected in the 0.5-2.5 keV range in 11 gl obular clusters. In Ter 6 a previously unknown sources was detected by Rosat; the source H1825-331 was confirmed to be in the cluster NGC 66 52; the persistent flux of the known burst source in Ter 5 was also de detected for the first time. The sources in Ter 5 and NGC 6652 are tr ansients, seen by Rosat in their bright state. Improved positions are obtained for the sources in NGC 6652, Ter 5, and Ter 6. From our analy sis of the area surrounding omega Cen, we suggest that only one of the five sources detected by Einstein is related to the globular cluster. One source was detected in the 0.07-0.5 keV band only, in NGC 5272. A fit of a blackbody to the spectrum of the source in NGC 5272 gives a temperature of similar to 45 eV, and a bolometric luminosity of simila r to 1.3 x 10(35) erg s(-1). Upper limits of sources in clusters for w hich only HEAO-1 observations were available have been improved by fac tors ten to hundred, and indicate that most clusters do not contain so urces with luminosities L(x)(0.5-2.5 keV) > 3 x 10(32) erg s(-1).