On the contribution of point sources to the Galactic ridge X-ray emission

Abstract

We analyzed deep Chandra observations of the Galactic plane region centered at l=28.55, b=-0.03 with the aim to obtain the best possible constraints on the contribution of weak point sources to the Galactic ridge X-ray emission (GRXE) in this region. We demonstrate that the vast majority of the detected sources are Galactic in origin and are probably cataclysmic variables and coronally active stars. We use the number-flux function of detected sources to constrain the luminosity function of Galactic X-ray sources in the range 1e30--1e32 erg/s and find good agreement with the luminosity function of sources in the Solar vicinity. The fraction of the total flux at energies 1--7 keV resolved into point sources at the current sensitivity level is ~25%. Excluding the expected contribution of extragalactic sources, ~19% of the GRXE is due to point Galactic sources with interstellar absorption corrected fluxes higher than 1.2e-15 erg/s/cm^2in the energy band 1-7 keV.

arXiv comment7 pages, 5 figures, Submitted to A&A

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• White dwarf masses in intermediate polars observed with the Suzaku satellite
• Low-mass X-ray binaries in the bulge of the Milky Way
• Spectral Study of the Galactic Ridge X-ray Emission with Suzaku
• Dominance of Magnetic Cataclysmic Variables in the Resolved Galactic Ridge X-ray Emission of the Limiting Window
• Diffuse X-Ray Sky in the Galactic Center
• Origin of the Galactic Diffuse X-ray Emission: Iron K-shell Line Diagnostics
• Low-luminosity X-ray sources and the Galactic ridge X-ray emission
• Suzaku Detection of Extended/Diffuse Hard X-Ray Emission from the Galactic Center
• Suzaku and Optical Spectroscopic Observations of SS 433 in the 2006 April Multiwavelength Campaign
• The Norma Arm Region Chandra Survey: X-ray Populations in the Spiral Arms
• Unveiling the soft X-ray source population towards the inner Galactic disk with XMM-Newton
• Updated Constraints on the Injection Energy of Positrons Generating the Galactic 511 keV $\gamma$-ray line