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Full-Text Articles in Physical Sciences and Mathematics
The Cos-Halos Survey: Rationale, Design, And A Census Of Circumgalactic Neutral Hydrogen, Jason Tumlinson, Christopher Thom, Jessica K. Werk, J. Xavier Prochaska, Todd M. Tripp, Neal S. Katz, Romeel Dave, Benjamin D. Oppenheimer, Joseph D. Meiring, Amanda Brady Ford, John M. O'Meara, Molly S. Peeples, Kenneth R. Sembach, David H. Weinberg
The Cos-Halos Survey: Rationale, Design, And A Census Of Circumgalactic Neutral Hydrogen, Jason Tumlinson, Christopher Thom, Jessica K. Werk, J. Xavier Prochaska, Todd M. Tripp, Neal S. Katz, Romeel Dave, Benjamin D. Oppenheimer, Joseph D. Meiring, Amanda Brady Ford, John M. O'Meara, Molly S. Peeples, Kenneth R. Sembach, David H. Weinberg
Neal S. Katz
We present the design and methods of the COS-Halos survey, a systematic investigation of the gaseous halos of 44 z = 0.15-0.35 galaxies using background QSOs observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. This survey has yielded 39 spectra of z em sime 0.5 QSOs with S/N ~10-15 per resolution element. The QSO sightlines pass within 150 physical kpc of the galaxies, which span early and late types over stellar mass log M */M ☉ = 9.5-11.5. We find that the circumgalactic medium exhibits strong H I, averaging sime 1 Å in Lyα equivalent width out …
The High-Ion Content And Kinematics Of Low-Redshift Lyman Limit Systems, Andrew J. Fox, Nicolas Lehner, Jason Tumlinson, J. Christopher Howk, Todd M. Tripp, J. Xavier Prochaska, John M. O'Meara, Jessica K. Werk, Rognmon Bordoloi, Neal S. Katz, Benjamin D. Oppenheimer, Romeel Dave
The High-Ion Content And Kinematics Of Low-Redshift Lyman Limit Systems, Andrew J. Fox, Nicolas Lehner, Jason Tumlinson, J. Christopher Howk, Todd M. Tripp, J. Xavier Prochaska, John M. O'Meara, Jessica K. Werk, Rognmon Bordoloi, Neal S. Katz, Benjamin D. Oppenheimer, Romeel Dave
Neal S. Katz
We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv 90 statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ~ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ~ 108.5-10.9 (r/150 kpc)2 M ☉, similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.