Global distribution of Fe Kα lines in the galactic center region observed with the Suzaku satellite

Abstract

We surveyed spatial profiles of the Fe Kα lines in the Galactic center diffuse X-rays (GCDX), including the transient region from the GCDX to the Galactic ridge X-ray emission (GRXE), with the Suzaku satellite. We resolved Fe Kα line complex into three lines of Fe I, Fe XXV, and Fe XXVI Kα, and obtained their spatial intensity profiles with a resolution of ∼0.°1. We compared the Fe XXV Kα profile with a stellar mass distribution (SMD) model made from near infrared observations. The intensity profile of Fe XXV Kα was nicely fitted with the SMD model in the GRXE region, while that in the GCDX region showed a 3.8±0.3 (0.°2 < |l| < 1.°5) or 19±6 (|l | < 0.°2) times excess over the best-fit SMD model in the GRXE region. Thus, Fe XXV Kα in the GCDX is hardly explained by the same origin of the GRXE. In the case of a point-source origin, a new population with the extremely strong Fe XXV Kα line is required. An alternative possibility is that the majority of the GCDX is truly diffuse optically thin thermal plasma. © 2011. Astronomical Society of Japan.