Detection of an extended soft X-ray source H2326-79 in the southern sky

Abstract

A new extended soft X-ray source H 2326-79 has been detected with the low energy detectors of the HEAO1 A-2 experiment. The source is found to have a size of approximately 2.5 arcsec and is centered at RA(1950)=23 h 26 m, Decl.(1950)= -79 deg 24 min. The observed energy flux, seen mainly in the 0.18-0.4 keV band, corrected for finite source size, is found to be about 2.6 x 10 to the -11th erg/sq cm-sec. It is determined that the source spectrum fits well with either an exponential model (gaunt factor included) or with a Raymond Smith plasma model. The observed characteristics of the source are studied for two physical models: a very old low surface brightness supernova remnant undetected in the radio and optical regions, and an enhanced X-ray emission region surrounding an H I cloud embedded in the hot cavity of Loop I. The observed source is also interpreted as a group of two or more unresolved stellar X-ray sources.