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Full-Text Articles in Physical Sciences and Mathematics
The Cos-Halos Survey: Physical Conditions And Baryonic Mass In The Low-Redshift Circumgalactic Medium, Jessica K. Werk, J. Xavier Prochaska, Jason Tumlinson, Molly S. Peeples, Todd M. Tripp, Andrew J. Fox, Nicolas Lehner, Christopher Thom, John M. O'Meara, Amanda Brady Ford, Rongmon Bordoloi, Neal S. Katz, Nicolas Tejos, Benjamin D. Oppenheimer, Romeel Dave, David H. Weinberg
The Cos-Halos Survey: Physical Conditions And Baryonic Mass In The Low-Redshift Circumgalactic Medium, Jessica K. Werk, J. Xavier Prochaska, Jason Tumlinson, Molly S. Peeples, Todd M. Tripp, Andrew J. Fox, Nicolas Lehner, Christopher Thom, John M. O'Meara, Amanda Brady Ford, Rongmon Bordoloi, Neal S. Katz, Nicolas Tejos, Benjamin D. Oppenheimer, Romeel Dave, David H. Weinberg
Neal S. Katz
We analyze the physical conditions of the cool, photoionized (T ~104 K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpc of L ~ L* galaxies at z ~ 0.2. These data are well described by simple photoionization models, with the gas highly ionized (n H II /n H gsim 99%) by the extragalactic ultraviolet background. Scaling by estimates for the virial radius, R vir, we show that the ionization state (tracked by the dimensionless ionization parameter, U) increases with distance from the host galaxy. The ionization parameters imply a …