Astron. Astrophys. 349, L49-L52 (1999)

1. Introduction

The diffuse X-ray emission from the Galactic Center (GC) region was imaged for the first time with the Einstein Observatory in the 0.5-4 keV band (Watson et al. 1981) and later studied in more detail with several satellites (Kawai et al. 1988, Skinner et al. 1987, Koyama et al. 1989, 1996). The real nature of this emission is still an open issue. Though at least part of it can be due to the integrated emission from weak unresolved sources (Watson et al. 1981; Zane, Turolla & Treves 1996), there is evidence that a hot plasma, responsible for the observed emission lines, permeates the GC region. This was indicated by the Ginga discovery of a strong iron line at 6.7 keV with an equivalent width of 70 eV (Koyama et al. 1989). More recently, the ASCA satellite confirmed the presence of a hot plasma (kT keV) and discovered another diffuse component in the 6.4 keV Fe-line with an asymmetric spatial distribution with respect to the GC and well correlated with the distribution of the giant molecular clouds (Koyama et al. 1996). The data on the diffuse X-ray emission reported here were obtained during a survey of the GC performed with the BeppoSAX Narrow Field Instruments (Sidoli et al. 1998). The results on the point sources have been reported elsewhere (Sidoli et al. 1999a, 1999b).

© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999
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