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Title: QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY

Abstract

The bimodality in galaxy properties has been observed at low and high redshifts, with a clear distinction between star-forming galaxies in the blue cloud and passively evolving objects in the red sequence; the absence of galaxies with intermediate properties indicates that the quenching of star formation and subsequent transition between populations must happen rapidly. In this paper, we present a study of over 100 transiting galaxies in the so-called green valley at intermediate redshifts (z {approx} 0.8). By using very deep spectroscopy with the DEIMOS instrument at the Keck telescope we are able to infer the star formation histories of these objects and measure the stellar mass flux density transiting from the blue cloud to the red sequence when the universe was half its current age. Our results indicate that the process happened more rapidly and for more massive galaxies in the past, suggesting a top-down scenario in which the massive end of the red sequence is forming first. This represents another aspect of downsizing, with the mass flux density moving toward smaller galaxies in recent times.

Authors:
;  [1]; ;  [2];  [3]
  1. Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Saude 20080-090 Rio de Janeiro (Brazil)
  2. California Institute of Technology, MC 278-17, Pasadena, CA 91125 (United States)
  3. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
22086446
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COSMOLOGY; EMISSION SPECTROSCOPY; FLUX DENSITY; GALACTIC EVOLUTION; GALAXIES; LUMINOSITY; MASS; QUENCHING; RED SHIFT; STARS; TELESCOPES; UNIVERSE

Citation Formats

Goncalves, Thiago S., Menendez-Delmestre, Karin, Martin, D. Christopher, Wyder, Ted K., and Koekemoer, Anton, E-mail: tsg@astro.ufrj.br. QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/1/67.
Goncalves, Thiago S., Menendez-Delmestre, Karin, Martin, D. Christopher, Wyder, Ted K., & Koekemoer, Anton, E-mail: tsg@astro.ufrj.br. QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY. United States. doi:10.1088/0004-637X/759/1/67.
Goncalves, Thiago S., Menendez-Delmestre, Karin, Martin, D. Christopher, Wyder, Ted K., and Koekemoer, Anton, E-mail: tsg@astro.ufrj.br. Thu . "QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY". United States. doi:10.1088/0004-637X/759/1/67.
@article{osti_22086446,
title = {QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY},
author = {Goncalves, Thiago S. and Menendez-Delmestre, Karin and Martin, D. Christopher and Wyder, Ted K. and Koekemoer, Anton, E-mail: tsg@astro.ufrj.br},
abstractNote = {The bimodality in galaxy properties has been observed at low and high redshifts, with a clear distinction between star-forming galaxies in the blue cloud and passively evolving objects in the red sequence; the absence of galaxies with intermediate properties indicates that the quenching of star formation and subsequent transition between populations must happen rapidly. In this paper, we present a study of over 100 transiting galaxies in the so-called green valley at intermediate redshifts (z {approx} 0.8). By using very deep spectroscopy with the DEIMOS instrument at the Keck telescope we are able to infer the star formation histories of these objects and measure the stellar mass flux density transiting from the blue cloud to the red sequence when the universe was half its current age. Our results indicate that the process happened more rapidly and for more massive galaxies in the past, suggesting a top-down scenario in which the massive end of the red sequence is forming first. This represents another aspect of downsizing, with the mass flux density moving toward smaller galaxies in recent times.},
doi = {10.1088/0004-637X/759/1/67},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}