Contributed Talk - Splinter eROSITA

Wednesday, 14 September 2022, 14:00   (SFG 0140 / virtual eROSITA)

The Milky Way hot circumgalactic medium as seen by eROSITA

Locatelli N., Zheng X., Ponti G., Freyberg M., Yeung M. et al.

The first all-sky maps of high ionization lines observed in X-rays by eROSITA provide an excellent probe for the study of the hot phase (T~10^6 K) of the Milky Way circumgalactic medium. In this work we analyse the maps of the O_VII, OVIII, Ne_IX and Ne_X lines, detected in the eROSITA data. These ~full-sky maps are a first ever of their kind, long awaited since the detection of soft-X background features in the ROSAT broad energy range maps. Thanks to the combination of the eROSITA large effective area, high energy and angular resolution, the different components of the sof-X background can now be finally separated and constrained. While the maps will soon be presented in a separate work, my contribution will focus on the fit of these sky maps, made in narrow energy bins around the emission lines, using physically-motivated emission models embedded in a 3D geometry. I will present the constraints put on the density distribution of the hot phase of the circumgalactic medium around our Galaxy, unveiling its geometry with a high statistical significance for the first time.