the COS-Dwarfs survey: the carbon reservoir around sub-L* galaxies
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- UCO/Lick Observatory, University of California, Santa Cruz, CA 95140 (United States)
- Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- University of the Western Cape, Bellville, Cape Town 7535 (South Africa)
- Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
- Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)
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 for 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.
- OSTI ID:
- 22370113
- Journal Information:
- Astrophysical Journal, Vol. 796, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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