Not Dead Yet: Cool Circumgalactic Gas in the Halos of Early Type Galaxies

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We report new observations of circumgalactic gas in the halos of early type galaxies obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope.

• We find that detections of HI surrounding early type galaxies are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations.
• For early type galaxies, the covering fraction for HI absorption above 10^16 cm^2 is ~40-50% within ~150 kpc.
• Line widths and kinematics of the detected material show it to be cold (T ~< 10^5 K) in comparison to the virial temperature of the host halos.