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

TL;DR

This study analyzes the scale heights and equivalent widths of iron K-shell lines in the Galactic diffuse X-ray emission, decomposing it into components and comparing with stellar source populations.

Contribution

It provides new measurements of scale heights and equivalent widths for different Galactic regions, enhancing understanding of their origins.

Findings

Confirmed the decomposition of GDXE into GCXE, GBXE, and GRXE.

Measured scale heights of Fe lines for each component.

Compared line properties with stellar source populations.

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 K alpha (6.4 keV), Fe XXV,He alpha (6.7 keV) and Fe XXVI Ly alpha (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 He alpha line of the GCXE, GBXE and GRXE are determined to be ~40, ~310 and ~140 pc, while those of the Fe I K alpha line are ~30, ~160 and ~70 pc, respectively. The mean equivalent widths (EWs) of the sum of the Fe XXV He alpha and Fe XXVI Ly alpha lines are ~750 eV, ~600 eV and ~550 eV, while those of the Fe I K alpha 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 (CVs), Active Binaries (ABs) and Coronal Active stars (CAs).