Astrophys. J., Suppl. Ser., 230, 6-6 (2017/May-0)
Characterizing the circumgalactic medium of nearby galaxies with HST/COS and HST/STIS absorption-line spectroscopy. II. Methods and models.
KEENEY B.A., STOCKE J.T., DANFORTH C.W., SHULL J.M., PRATT C.T., FRONING C.S., GREEN J.C., PENTON S.V. and SAVAGE B.D.
Abstract (from CDS):
We present basic data and modeling for a survey of the cool, photoionized circumgalactic medium (CGM) of low-redshift galaxies using far-UV QSO absorption-line probes. This survey consists of "targeted" and "serendipitous" CGM subsamples, originally described in Stocke et al. (Paper I). The targeted subsample probes low-luminosity, late-type galaxies at z 0.02 with small impact parameters (<ρ>=71 kpc), and the serendipitous subsample probes higher luminosity galaxies at z 0.2 with larger impact parameters (<ρ>=222 kpc). Hubble Space Telescope and FUSE UV spectroscopy of the absorbers and basic data for the associated galaxies, derived from ground-based imaging and spectroscopy, are presented. We find broad agreement with the COS-Halos results, but our sample shows no evidence for changing ionization parameter or hydrogen density with distance from the CGM host galaxy, probably because the COS-Halos survey probes the CGM at smaller impact parameters. We find at least two passive galaxies with H I and metal-line absorption, confirming the intriguing COS-Halos result that galaxies sometimes have cool gas halos despite no on-going star formation. Using a new methodology for fitting H I absorption complexes, we confirm the CGM cool gas mass of Paper I, but this value is significantly smaller than that found by the COS-Halos survey. We trace much of this difference to the specific values of the low-z metagalactic ionization rate assumed. After accounting for this difference, a best-value for the CGM cool gas mass is found by combining the results of both surveys to obtain log(M/M☉)=10.5±0.3, or ∼30% of the total baryon reservoir of an L L* , star-forming galaxy.
© 2017. The American Astronomical Society. All rights reserved.
galaxies: dwarf - galaxies: groups: general - galaxies: halos - galaxies: spiral - intergalactic medium - quasars: absorption lines - quasars: absorption lines
VizieR on-line data:
<Available at CDS (J/ApJS/230/6): table1.dat table2.dat table3.dat>
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