Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/0701483)
· On-line Data
· References in the article
· Citations to the Article (35) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (3)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
The Cosmic Evolution Survey (COSMOS): The Morphological Content and Environmental Dependence of the Galaxy Color-Magnitude Relation at z ~ 0.7
Authors:
Cassata, P.; Guzzo, L.; Franceschini, A.; Scoville, N.; Capak, P.; Ellis, R. S.; Koekemoer, A.; McCracken, H. J.; Mobasher, B.; Renzini, A.; Ricciardelli, E.; Scodeggio, M.; Taniguchi, Y.; Thompson, D.
Affiliation:
AA(INAF-Instituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, I-20133 Milano, Italy.; Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, I-35122 Padova, Italy.), AB(INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (LC), Italy.; Visiting Scientist, ESO and MPA/MPE, Garching, Germany.), AC(Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, I-35122 Padova, Italy.), AD(California Institute of Technology, 1200 East California Boulevard, MC 105-24, Pasadena, CA 91125.; Visiting Astronomer, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822.), AE(California Institute of Technology, 1200 East California Boulevard, MC 105-24, Pasadena, CA 91125.), AF(California Institute of Technology, 1200 East California Boulevard, MC 105-24, Pasadena, CA 91125.), AG(Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218.), AH(Institut d'Astrophysique de Paris, CNRS, Université Pierre et Marie Curie, UMR 7095, 98 bis Boulevard Arago, 75014 Paris, France.), AI(Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218.), AJ(INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy.), AK(Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, I-35122 Padova, Italy.), AL(INAF-Instituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, I-20133 Milano, Italy.), AM(Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan.), AN(California Institute of Technology, 1200 East California Boulevard, MC 105-24, Pasadena, CA 91125.; Large Binocular Telescope Observatory, 933 North Cherry Avenue, Tucson, AZ 85721-0065.)
Publication:
The Astrophysical Journal Supplement Series, Volume 172, Issue 1, pp. 270-283. (ApJS Homepage)
Publication Date:
09/2007
Origin:
UCP
ApJ Keywords:
Galaxies: Clusters: General, Galaxies: Evolution, Galaxies: General, Galaxies: Structure, Cosmology: Large-Scale Structure of Universe
DOI:
10.1086/516591
Bibliographic Code:
2007ApJS..172..270C

Abstract

We study the environmental dependence and the morphological composition of the galaxy color-magnitude diagram at z~0.7, using a pilot subsample of COSMOS. The sample includes ~2000 galaxies with IAB<24 and photometric redshift within 0.61<z<0.85, covering an area of 270 arcmin2. Galaxy morphologies are estimated via a nonparametric automatic technique. The (V-z') versus z' color-magnitude diagram shows a clear red sequence dominated by early-type galaxies and a remarkably well-defined ``blue sequence'' described by late-type objects. While the percentage of objects populating the two sequences is a function of environment, also following a clear morphology/color-density relation at this redshift, we establish that their normalization and slope are independent of local density. We identify and study a number of objects with ``anomalous'' colors, given their morphology, polluting the two sequences. Red late-type galaxies are found to be mostly highly inclined or edge-on spiral galaxies for which colors are dominated by internal reddening by dust. In a sample of color-selected red galaxies, these would represent 33% contamination with respect to truly passive spheroidals. Conversely, the population of blue early-type galaxies is composed of objects of moderate luminosity and mass, concurring to only ~5% of the mass in spheroidal galaxies. The majority of them (~70%) occupy a position in the μB-r50 plane not consistent with their being precursors of current-epoch elliptical galaxies. Their fraction with respect to the whole galaxy population does not depend on the environment, at variance with the general early-type class. In a color-mass diagram, color sequences are even better defined, with red galaxies covering in general a wider range of masses at nearly constant color, and blue galaxies showing a more pronounced dependence of color on mass. While the red sequence is adequately reproduced by models of passive evolution, the blue sequence is better interpreted as a specific star formation sequence. The substantial invariance of its slope and normalization with respect to local density suggests that the overall ``secular'' star formation is driven more by galaxy mass than by environment.

Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555 also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by AURA, Inc., under cooperative agreement with the National Science Foundation; the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.; and the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii.

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints