On the OVI Abundance in the Circumgalactic Medium of Low-Redshift Galaxies
Name
1511.00687.pdf
Description
Submitted version
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4.37 MB
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Author(s)
Suresh, Joshua
Rubin, Kate HR
Kannan, Rahul
Werk, Jessica K
Hernquist, Lars
Vogelsberger, Mark
Date Issued
2017
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Suresh, Joshua, et al. "On the Ovi Abundance in the Circumgalactic Medium of Low-Redshift Galaxies." Monthly Notices of the Royal Astronomical Society 465 3 (2017): 2966-82.
Version
Original manuscript
Abstract
© 2016 The Authors. We analyse the mass, temperature, metal enrichment, and OVI abundance of the circumgalactic medium (CGM) around z ~ 0.2 galaxies of mass 109M⊙ < M* < 1011.5M⊙ in the Illustris simulation. Among star-forming galaxies, the mass, temperature, and metallicity of the CGM increase with stellar mass, driving an increase in the OVI column-density profile of ~0.5 dex with each 0.5 dex increase in stellar mass. Observed OVI column-density profiles exhibit a weaker mass dependence than predicted; the simulated OVI abundance profiles are consistent with those observed for star-forming galaxies of mass M* = 1010.5-11.5M⊙, but underpredict the observed OVI abundances by ≳0.8 dex for lower mass galaxies. We suggest that this discrepancy may be alleviated with additional heating of the abundant cool gas in low-mass haloes, or with increased numerical resolution capturing turbulent/conductive mixing layers between CGM phases. Quenched galaxies of mass M* = 1010.5-11.5M⊙ are found to have 0.3-0.8 dex lower OVI column-density profiles than star-forming galaxies of the same mass, in qualitative agreement with the observed OVI abundance bimodality. This offset is driven by AGN feedback, which quenches galaxies by heating theCGMand ejecting significant amounts of gas from the halo. Finally, we find that the inclusion of the central-galaxy's radiation field may enhance the photoionization of the CGM within ~50 kpc, further increasing the predicted OVI abundance around star-forming galaxies.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STW2499
