TY - JOUR
T1 - A stellar mass threshold for quenching of field galaxies
AU - Geha, M.
AU - Blanton, M. R.
AU - Yan, R.
AU - Tinker, J. L.
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2012/9/20
Y1 - 2012/9/20
N2 - 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 (EWHα < 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.
AB - 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 (EWHα < 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.
KW - galaxies: dwarf
KW - galaxies: stellar content
KW - methods: statistical
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U2 - 10.1088/0004-637X/757/1/85
DO - 10.1088/0004-637X/757/1/85
M3 - Article
AN - SCOPUS:84866100466
VL - 757
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 85
ER -