Cool and warm-hot circumgalactic medium around massive quenched luminous red galaxies

We study the circumgalactic medium (CGM) around massive quenched luminous red galaxies (LRGs) at z~0.5, with the projected distances from the LRG of up to 400 kpc. We observed UV absorption lines, including HI, OVI, CIII, and other lines. In the CGM of two LRGs, we found strong and extended metal (CIII) and HI absorption lines, with CIII equivalent widths and velocity spreads exceeding all local ~L* galaxies. This result shows that massive quenched galaxies could contain significant amounts of cool gas in their CGM. Next, previous studies found that for L* and sub-L* galaxies, the CGM HI 1215 absorption (that is tracing cool CGM gas) is stronger as galaxies are more massive. However, when we included LRGs, we found that the cool CGM is suppressed above stellar masses of log M* ~ 11.5. Next, we found that while LRGs usually do not show detectable OVI in their CGM, in some cases LRG CGM systems show relatively strong OVI absorption, and in these cases the OVI is likely associated with blue star-forming neighboring galaxies.