Faint Hard X-ray Sources in the Galactic Center Region: Supernova Ejecta Fragments Population

Abstract

Long Chandra observations of 17 arcmin x 17 arcmin field in the Galactic Center (GC) region reported by Muno et. al. (2003) have revealed a population of about 2,000 hard faint X-ray sources limited by luminosities Lx > 10(31} erg/s. We show that fast moving knots (FMKs) of supernovae ejecta could comprise a sizeable fraction of the sources. Each supernova event can produce hundreds of FMKs. The presence of ~ 3 supernova remnants of age ~ 1,000 years in the GC region could provide the required number of the FMKs. Simulated X-ray spectra of the FMKs contain both thermal and nonthermal components. The nonthermal spectra are power-laws with hard photon indexes 0 < Gamma < 1.5 and prominent lines of some metals (e.g. Fe). The logN-logS distribution and the hardness ratios of the FMKs in the GC region are consistent with the Chandra findings. Spatial distribution of the FMKs in the GC region should appear as an ensemble of coherent shell and jet-like structures of a few arcmin-scale.