The Circumgalactic Medium ( CGM ) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z \leq 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph and \sim 60 serendipitous absorber/galaxy pairs at z \leq 0.2 with the Space Telescope Imaging Spectrograph .
CGM warm cloud properties are derived , including volume filling factors of 3–5 % , cloud sizes of 0.1–30 kpc , masses of 10– 10 ^ { 8 } ~ { } M _ { \odot } and metallicities of \sim 0.1 – 1 Z _ { \sun } .
Almost all warm CGM clouds within 0.5 R _ { vir } are metal-bearing and many have velocities consistent with being bound , “ galactic fountain ” clouds .
For galaxies with L \gtrsim 0.1 L ^ { * } , the total mass in these warm CGM clouds approaches 10 ^ { 10 } ~ { } M _ { \odot } , \sim 10 –15 % of the total baryons in massive spirals and comparable to the baryons in their parent galaxy disks .
This leaves \gtrsim 50 % of massive spiral-galaxy baryons “ missing ” .
Dwarfs ( < 0.1 L ^ { * } ) have smaller area covering factors and warm CGM masses ( \leq 5 % baryon fraction ) , suggesting that many of their warm clouds escape .
Constant warm cloud internal pressures as a function of impact parameter ( P / k \sim 10 ~ { } { cm ^ { -3 } K } ) support the inference that previous COS detections of broad , shallow O vi and { Ly } \alpha absorptions are of an extensive ( \sim 400 –600 kpc ) , hot ( T \approx 10 ^ { 6 } K ) intra-cloud gas which is very massive ( \geq 10 ^ { 11 } ~ { } M _ { \odot } ) .
While the warm CGM clouds can not account for all the “ missing baryons ” in spirals , the hot intra-group gas can , and could account for \sim 20 % of the cosmic baryon census at z \sim 0 if this hot gas is ubiquitous among spiral groups .