eRASS1 X-ray sources Sco-Cen members

Bona fide Sco-Cen member stars are young and are therefore expected to emit X-rays at the saturation level. By cross-correlating the eRASS1 source catalog with the Gaia EDR3 catalog, we arrive at a complete identification of the stellar (i.e., coronal) source content of eROSITA in the Sco-Cen association, and in particular obtain for the first time a 3D view of the detected stellar X-ray sources.

Focusing on the low-mass population and placing the optical counterparts identified in this way in a color-magnitude diagram, we can isolate the young stars out of the detected X-ray sources and obtain age estimates of the various Sco-Cen populations. A joint analysis of the 2D and 3D space motions, the latter being available only for a smaller subset of the detected stellar X-ray sources, reveals that the space motions of the selected population show a high degree of parallelism, but there is also an additional population of young, X-ray emitting and essentially cospatial stars that appears to be more diffuse in velocity space.