Confirm cold-front nature of the southern surface-brightness discontinuity in Virgo

Determine whether the surface brightness discontinuity observed between 40–60 arcminutes (approximately 220 kpc) south of M87 in the Virgo Cluster is consistent with a cold front along its entire azimuthal extent, including the SSW, SSE, and WSW sectors, by verifying the characteristic temperature decrease and density increase across the interface relative to previously analyzed segments at 233 kpc (west) and 280 kpc (south).

Background

eROSITA imaging and surface-brightness analysis reveal two prominent discontinuities in Virgo: a well-studied northern feature at ~90 kpc that prior XMM-Newton, Suzaku, and Chandra spectroscopy has established as a cold front, and a southern feature between ~40–60 arcminutes (~220 kpc) that appears less sharp. Prior Suzaku studies identified cold-front signatures at two locations along the southern/western directions (233 kpc and 280 kpc), but did not cover the full extent seen here.

Cold fronts are distinguished from shocks by a drop in temperature and a jump in density across the interface. While segments of the southern discontinuity have been spectroscopically confirmed, the present eROSITA analysis highlights the full arc-like structure for the first time, motivating a comprehensive confirmation of cold-front characteristics along the entire observed extent.