Abstract and slides by speaker > Berg Michelle

Luminous red galaxies (LRGs) are some of the most massive objects and have been quiescent since z~1. According to the prevailing theory of galaxy evolution, any gas accreted into the circumgalactic medium (CGM) about these massive galaxies (log M_h ~ 13.7 M⊙) should be shock-heated to very high temperatures. We put this theory to the test using a sample of 21 LRGs with QSO sightlines piercing their CGM out to a distance of 500 kpc. From these observations we detect 4 Lyman limit systems (LLSs, 16 ≤ log(N_HI) ≤ 19 cm^-2); three of the absorbers are metal-rich, and one is metal-poor ([X/H]=−1.8). Using a limit of log(N_HI) ≥ 16, we find a covering factor of strong HI in the halos of LRGs to be 31% within R_vir. The presence of cool (T~10^4 K) gas in the LRG halos is unexpected, as is the presence of a low-metallicity LLS that may trace recent accretion onto the LRG. A large reservoir of cool gas is found around these red and dead galaxies, but they are not using it for star formation.