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Title: the COS-Dwarfs survey: the carbon reservoir around sub-L* galaxies

We report new observations of circumgalactic gas from the COS-Dwarfs survey, a systematic investigation of the gaseous halos around 43 low-mass z ≤ 0.1 galaxies using background QSOs observed with the Cosmic Origins Spectrograph. From the projected one-dimensional and two-dimensional distribution of C IV absorption, we find that C IV is detected out to ≈100 kpc (corresponding roughly to ≈0.5 R {sub vir}) of the host galaxies. The C IV absorption strength falls off radially as a power law, and beyond ≈0.5 R {sub vir}, no C IV absorption is detected above our sensitivity limit of ≈50-100 mÅ. We find a tentative correlation between detected C IV absorption strength and star formation, paralleling the strong correlation seen in highly ionized oxygen for L ∼ L* galaxies by the COS-Halos survey. The data imply a large carbon reservoir in the circumgalactic medium (CGM) of these galaxies, corresponding to a minimum carbon mass of ≳ 1.2 × 10{sup 6} M {sub ☉} out to ∼110 kpc. This mass is comparable to the carbon mass in the interstellar medium and exceeds the carbon mass currently in the stars of these galaxies. The C IV absorption seen around these sub-L* galaxies can account formore » almost two-thirds of all W{sub r} ≥ 100 mÅ C IV absorption detected at low z. Comparing the C IV covering fraction with hydrodynamical simulations, we find that an energy-driven wind model is consistent with the observations whereas a wind model of constant velocity fails to reproduce the CGM or the galaxy properties.« less
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3] ; ; ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  2. UCO/Lick Observatory, University of California, Santa Cruz, CA 95140 (United States)
  3. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)
  4. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  5. University of the Western Cape, Bellville, Cape Town 7535 (South Africa)
  6. Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
  7. Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)
  8. Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22370113
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 796; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; COMPUTERIZED SIMULATION; CORRELATIONS; DISTRIBUTION; DWARF STARS; ELEMENT ABUNDANCE; GALAXIES; HYDRODYNAMIC MODEL; MASS; OXYGEN; QUASARS; SENSITIVITY; SPECTROSCOPY; STAR EVOLUTION; STARS; STELLAR WINDS; VELOCITY