The cos-dwarfs survey: The carbon reservoir around sub-l∗ galaxies

Rongmon Bordoloi, Jason Tumlinson, Jessica K. Werk, Benjamin D. Oppenheimer, Molly S. Peeples, J. Xavier Prochaska, Todd M. Tripp, Neal Katz, Romeel Davé, Andrew J. Fox, Christopher Thom, Amanda Brady Ford, David H. Weinberg, Joseph N. Burchett, Juna A. Kollmeier

Research output: Contribution to journalReview articlepeer-review

193 Scopus citations


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 vir) of the host galaxies. The C IV absorption strength falls off radially as a power law, and beyond ≈0.5 R 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 × 106 M 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 Wr ≥ 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.

Original languageEnglish (US)
Article number136
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 1 2014
Externally publishedYes


  • galaxies: evolution
  • galaxies: general
  • galaxies: halos
  • intergalactic medium
  • quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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