eRASS1 source properties and classifications

We aim to classify and characterize faint X-ray sources detected in the eROSITA All-Sky Survey (eRASS1) toward the inner Galactic disk (350<l<360, -1<b<1) using deeper XMM-Newton observations (~20 ks). We analyzed 189 eRASS1 sources, combining X-ray spectral fitting (0.2-10keV) with Gaia astrometric and photometric data for robust classification.

Our results show that the eRASS1 catalog toward the Galactic disk is overwhelmingly dominated by coronal sources (~74%), primarily active stars and binaries, with ~8% being wind-powered massive stars and ~18% being accreting compact objects. We propose an empirical hardness-ratio cut (HR>-0.2) to efficiently isolate these non-coronal sources. By stacking the classified population and comparing with the Galactic Ridge X-ray Emission (GRXE) surface brightness, we estimate that ~6% of the GRXE flux in the 0.5-2.0keV band is resolved into point sources above the eRASS1 flux limit (~5x10^-14^erg/cm^2^/s).