Urrutia

Evidence of strong clumping in the inner CGM deduced via its electron densities
Using the extreme sensitivity and 140 hour exposure times in the MUSE eXtreme Deep Field (MXDF) in the Hubble Ultra Deep Field, we are able to probe the inner CGM of strongly star-forming galaxies in non-resonant emission lines out to redshift of ~1. Of particular interest, is the [OII]_3727 doublet, for which we are able to measure the electron densities out to 20-30kpc, at the edge between galaxies' outskirts and the inner CGM. To our surprise, we were able to measure the electron densities in a handful of galaxies above the low density limit, even though the ionization budget and the volume densities drop precipitously. This turns to evidence of strong clumping in these areas, the cool CGM (10^4K) ionization regions must be much smaller than 1kpc.