The hot gas mass fraction in halos

Aims. By using eROSITA data in the eFEDS area, we provide a measure of the f gas − M halo relation over the largest halo mass range, from Milky Way-sized halos to massive clusters, and to the largest radii ( R 200 ) ever probed so far in local systems at z < 0.2. Methods. To cope with incompleteness and selection biases of the X-ray selection, we applied the stacking technique in eROSITA data of a highly complete and tested sample of optically selected groups. The method has been extensively tested on mock observations. Results. In massive clusters, the hot gas alone provides a baryon budget within R 200 consistent with Ω b /Ω m , while at the group mass scale, it accounts only for 20–40% of the cosmic…

• ER
  European Research Council