A contribution of stellar flares to the GRXE -- based on MAXI observations --

TL;DR

This study estimates the contribution of stellar flares and cataclysmic variables to the Galactic Ridge X-ray Emission using MAXI observations, suggesting stellar flares are the primary source.

Contribution

It provides the first estimation of stellar flares' contribution to GRXE based on MAXI data and simulates the resulting thermal spectrum with emission lines.

Findings

Stellar flares likely dominate the GRXE thermal spectrum.

CVs contribute secondary high-temperature thermal emission.

The composite spectrum matches observed GRXE features.

Abstract

Using unbiased observations of MAXI/GSC the potential contribution of stellar flares and CVs to GRXE luminosity is estimated in the energy range of 2 - 10 keV. Currently, a reasonable luminosity has been obtained extrapolating the number of stellar flares and that of CVs toward the Galactic ridge from those of the observed flares and CVs near the solar system. The ionized emission lines of Si to Fe are also simulated making the composite thermal spectrum which is based on MAXI observations of stellar flares and CVs. The present estimated result strongly supports a picture that the cumulative stellar flares contribute primarily to the GRXE in terms of the composite thermal spectrum with emission lines and secondary contribution is due to the thermal spectrum with high temperature from CVs.