THE BUILDUP OF THE HUBBLE SEQUENCE IN THE COSMOS FIELD

Journal Article · Sat May 01 04:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/714/1/L47; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21305016

Oesch, P A; Carollo, C M; Feldmann, R; Hahn, O; Lilly, S J; Aller, M C; Bschorr, T; Kovac, K ^[1]; Sargent, M T ^[2]; Scarlata, C; Capak, P; Massey, R ^[3]; Aussel, H ^[4]; Bolzonella, M ^[5]; Bundy, K ^[6]; Ilbert, O ^[7]; Kneib, J -P ^[8]; Koekemoer, A M ^[9]; Leauthaud, A ^[10]; Le Floc'h, E ^[11]

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1. Institute for Astronomy, ETH Zurich, 8092 Zurich (Switzerland)
2. Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)
3. California Institute of Technology, MS 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
4. AIM Unite Mixte de Recherche CEA CNRS, Universite Paris VII UMR n158, Paris (France)
5. INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)
6. Astronomy Department, University of California, Berkeley, CA 94705 (United States)
7. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
8. Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France)
9. STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
10. LBNL and BCCP, University of California, Berkeley, CA 94720 (United States)
11. Service d'Astrophysique, CEA/Saclay, 91191 Gif-sur-Yvette (France)

We use {approx}8600 COSMOS galaxies at mass scales >5 x 10{sup 10} M {sub sun} to study how the morphological mix of massive ellipticals, bulge-dominated disks, intermediate-bulge disks, disk-dominated galaxies, and irregular systems evolves from z = 0.2 to z = 1. The morphological evolution depends strongly on mass. At M > 3 x 10{sup 11} M {sub sun}, no evolution is detected in the morphological mix: ellipticals dominate since z = 1, and the Hubble sequence has quantitatively settled down by this epoch. At the 10{sup 11} M {sub sun} mass scale, little evolution is detected, which can be entirely explained by major mergers. Most of the morphological evolution from z = 1 to z = 0.2 takes place at masses 5 x 10{sup 10}-10{sup 11} M {sub sun}, where (1) the fraction of spirals substantially drops and the contribution of early types increases. This increase is mostly produced by the growth of bulge-dominated disks, which vary their contribution from {approx}10% at z = 1 to >30% at z = 0.2 (for comparison, the elliptical fraction grows from {approx}15% to {approx}20%). Thus, at these masses, transformations from late to early types result in diskless elliptical morphologies with a statistical frequency of only 30%-40%. Otherwise, the processes which are responsible for the transformations either retain or produce a non-negligible disk component. (2) The disk-dominated galaxies, which contribute {approx}15% to the intermediate-mass galaxy population at z = 1, virtually disappear by z = 0.2. The merger rate since z = 1 is too low to account for the disappearance of these massive disk-dominated systems, which most likely grow a bulge via secular evolution.

• OSTI ID: 21305016
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 714; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
GALACTIC EVOLUTION
GALAXIES
MASS
MORPHOLOGY
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