By Smita Mathur

One of the major goals of Athena is to find the cosmic baryons that are still missing, and that are expected to be present in the intergalactic medium and the circumgalactic medium (CGM). The hot gas in the CGM can be probed by X-ray absorption lines. While this is done effectively for the Milky Way, probing the CGM of external galaxies with X-ray absorption lines has been difficult.

In this paper, we targeted a unique sightline showing broad OVI absorption in the UV and found tentative evidence of the hot gas using Chandra observations. We show that we can easily detect the OVII absorption line, the telltale sign of the hotter gas, with Athena. The high sensitivity and spectral resolution of Athena will revolutionize the CGM science

 Access to the manuscript in ADS.