THE RELATIVE ABUNDANCE OF COMPACT AND NORMAL MASSIVE EARLY-TYPE GALAXIES AND ITS EVOLUTION FROM REDSHIFT z {approx} 2 TO THE PRESENT
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- Osservatorio Astronomico di Padova (INAF-OAPD), Vicolo dell'Osservatorio 5, I-35122 Padova (Italy)
- Space Telescope Science Institute, 3700 San Martin Boulevard, Baltimore, MD 21218 (United States)
- School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States)
- University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom)
- NOAO-Tucson, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
We report on the evolution of the number density and size of early-type galaxies (ETGs) from z {approx} 2 to z {approx} 0. We select a sample of 563 massive (M > 10{sup 10} M{sub Sun }), passively evolving (specific star formation rate <10{sup -2} Gyr{sup -1}), and morphologically spheroidal galaxies at 0 < z < 2.5, using the panchromatic photometry and spectroscopic redshifts available in the Great Observatories Origins Deep Surveys fields. We combine Advanced Camera for Surveys and Wide Field Camera 3 Hubble Space Telescope images to study the morphology of our galaxies in their optical rest frame in the entire 0 < z < 2.5 range. We find that throughout the explored redshift range the passive galaxies selected with our criteria have weak morphological K-correction, with size being slightly smaller in the optical than in the UV rest frame (by {approx}20% and {approx}10% at z > 1.2 and z < 1.2, respectively). We measure a significant evolution of the mass-size relation of ETGs, with a fractional increment that is almost independent of the stellar mass. ETGs formed at z > 1 appear to be preferentially small, and the evolution of the mass-size relation at z < 1 is driven by both the continuous size growth of the compact galaxies and the appearance of new ETGs with large sizes. We also find that the number density of all passive ETGs increases rapidly, by a factor of five, from z {approx} 2 to z {approx} 1, and then more mildly by another factor of 1.5 from z {approx} 1 to z {approx} 0. We interpret these results as evidence that the bulk of the ETGs are formed at 1 < z < 3 through a mechanism that leaves very compact remnants. At z < 1 the compact ETGs grow gradually in size, becoming normal-size galaxies, and at the same time new ETGs with normal-large sizes are formed.
- OSTI ID:
- 22004510
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 743; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
A PANCHROMATIC CATALOG OF EARLY-TYPE GALAXIES AT INTERMEDIATE REDSHIFT IN THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE FIELD
THE STRUCTURE OF MASSIVE QUIESCENT GALAXIES AT Z {approx} 3 IN THE CANDELS-COSMOS FIELD