X-ray-to-optical flux ratio vs. Gaia color for the closest optical counterparts to the X-ray sources selected from the match of LG11-Gaia with the eRASS1 catalog. Two distinct regions are visible: the extra-galactic area with high log(f_x/f_G) values and relatively blue Gaia color, and the star region with lower values of log(f_x/f_G) and redder Gaia color, separated by the dashed black line we derived from Fig. B3 in Stelzer et al. 2022). The filled red squares are the 673 eRASS1 sources that we identified as M dwarfs (see text in Sect. 3.2), and the filled yellow squares represent the four stars that have a comoving companion. We show only the sources with Sep_X,opt < 3 x RADEC_ERR.