期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 442, 期 1, 页码 533-557出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stu808
关键词
galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation; galaxies: star formation
资金
- Research Corporation for Science Advancement under the Cottrell College Science Award [10777]
- Missouri Consortium of NASA's National Space Grant College and Fellowship Program
- EU FP7 [267251 AstroFIt]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Japan Participation Group
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Korean Scientist Group
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max-Planck-Institute for Astronomy (MPIA)
- Max-Planck-Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z <= 0.08) that have unusually blue optical colours. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c(r) >= 2.6). These blue ellipticals comprise 3.7 per cent of all c(r) >= 2.6 galaxies with stellar masses between 10(10) and 10(11) h(-2)M(circle dot). Using published fibre spectrum diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colours and young (<3Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7 x 10(-5) h(3) Mpc(-3) and sufficient numbers above 2.5 x 10(10) h(-2)M(circle dot) to account for more than half of the expected quiescent growth at late cosmic time assuming that this phase lasts 0.5 Gyr. RQEs have properties that are consistent with a recent merger origin (i.e. they are strong 'first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centres of <3 x 10(12) h(-1)M(circle dot) groups) agrees well with the 'small group scale' predicted for maximally efficient spiral merging on to their halo centre and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendants may heat the atmospheres of small host haloes sufficiently to maintain quenching.
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