Scale heights and equivalent widths of the iron K-shell lines in the Galactic diffuse X-ray emission

Abstract

This paper reports the analysis of the X-ray spectra of the Galactic diffuse X-ray emission (GDXE) in the Suzaku archive. The fluxes of the Fe I Kα (6.4 keV), Fe XXV Heα (6.7 keV), and Fe XXVI Lyα (6.97 keV) lines are separately determined. From the latitude distributions, we confirm that the GDXE is decomposed into the Galactic center (GCXE), the Galactic bulge (GBXE) and the Galactic ridge (GRXE) X-ray emissions. The scale heights (SHs) of the Fe XXV Heα line of the GCXE, GBXE, and GRXE are determined to be 40, 310, and 140 pc, while those of the Fe I Kα line are 30, 160, and 70 pc, respectively. The mean equivalent widths (EWs) of the sum of the Fe XXV Heα and Fe XXVI Lya lines are 750 eV, 600 eV, and 550 eV, while those of the Fe I Kα line are 150 eV, 60 eV, and 100 eV for the GCXE, GBXE, and GRXE, respectively. The origin of the GBXE, GRXE, and GCXE is separately discussed based on the new results of the SHs and EWs, in comparison with those of the cataclysmic variables, active binaries and coronal active stars.