A stellar mass threshold for quenching of field galaxies

M. Geha, M. R. Blanton, R. Yan, J. L. Tinker

    Research output: Contribution to journalArticlepeer-review

    Abstract

    We demonstrate that dwarf galaxies (107 < Mstellar < 109 M, -12 > Mr > -18) with no active star formation are extremely rare (<0.06%) in the field. Our sample is based on the NASA-Sloan Atlas which is a reanalysis of the Sloan Digital Sky Survey Data Release 8. We examine the relative number of quenched versus star-forming dwarf galaxies, defining quenched galaxies as having no Hα emission (EW < 2 Å) and a strong 4000 Å break. The fraction of quenched dwarf galaxies decreases rapidly with increasing distance from a massive host, leveling off for distances beyond 1.5Mpc. We define galaxies beyond 1.5Mpc of a massive host galaxy to be in the field. We demonstrate that there is a stellar mass threshold of Mstellar < 1.0 × 109 M below which quenched galaxies do not exist in the field. Below this threshold, we find that none of the 2951 field dwarf galaxies are quenched; all field dwarf galaxies show evidence for recent star formation. Correcting for volume effects, this corresponds to a 1σ upper limit on the quenched fraction of 0.06%. In more dense environments, quenched galaxies account for 23% of the dwarf population over the same stellar mass range. The majority of quenched dwarf galaxies (often classified as dwarf elliptical galaxies) are within 2 virial radii of a massive galaxy, and only a few percent of quenched dwarf galaxies exist beyond 4 virial radii. Thus, for galaxies with stellar mass less than 1.0 × 109 M, ending star formation requires the presence of a more massive neighbor, providing a stringent constraint on models of star formation feedback.

    Original languageEnglish (US)
    Article number85
    JournalAstrophysical Journal
    Volume757
    Issue number1
    DOIs
    StatePublished - Sep 20 2012

    Keywords

    • galaxies: dwarf
    • galaxies: stellar content
    • methods: statistical

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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