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Unpublished Paper
The High-Ion Content and Kinematics of Low-Redshift Lyman Limit Systems
Astrophysical Journal (2013)
  • 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, University of Massachusetts - Amherst
  • Benjamin D. Oppenheimer
  • Romeel Dave
Abstract
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.
Keywords
  • Intergalactic medium,
  • galaxies: halos,
  • galaxies: kinematics and dynamics
Publication Date
2013
Comments
Prepublished version downloaded from ArXiv. Published version is located at http://iopscience.iop.org/0004-637X/778/2/187
Citation Information
Andrew J. Fox, Nicolas Lehner, Jason Tumlinson, J. Christopher Howk, et al.. "The High-Ion Content and Kinematics of Low-Redshift Lyman Limit Systems" Astrophysical Journal (2013)
Available at: http://works.bepress.com/neal_katz/17/