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Title: COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS

Abstract

We present a comparison between the observed color distribution, number, and mass density of massive galaxies at 1.5 < z < 3 and a model by Hopkins et al. that relates the quasar and galaxy population on the basis of gas-rich mergers. In order to test the hypothesis that quiescent red galaxies are formed after a gas-rich merger involving quasar activity, we confront photometry of massive (M>4 x 10{sup 10} M{sub sun}) galaxies extracted from the FIRES, GOODS-South, and MUSYC surveys, together spanning an area of 496 arcmin{sup 2}, with synthetic photometry from hydrodynamical merger simulations. As in the Hopkins et al. model, we use the observed quasar luminosity function to estimate the merger rate. We find that the synthetic U - V and V - J colors of galaxies that had a quasar phase in their past match the colors of observed galaxies that are best characterized by a quiescent stellar population. At z {approx} 2.6, the observed number and mass density of quiescent red galaxies with M>4 x 10{sup 10} M{sub sun} is consistent with the model in which every quiescent massive galaxy underwent a quasar phase in the past. At z {approx} 1.9, 2.8 times less quiescentmore » galaxies are observed than predicted by the model as descendants of higher redshift quasars. The merger model also predicts a large number and mass density of galaxies undergoing star formation driven by the merger. We find that the predicted number and mass density accounts for 30%-50% of the observed massive star-forming galaxies. However, their colors do not match those of observed star-forming galaxies. In particular, the colors of dusty red galaxies (accounting for 30%-40% of the massive galaxy population) are not reproduced by the simulations. Several possible origins of this discrepancy are discussed. The observational constraints on the validity of the model are currently limited by cosmic variance and uncertainties in stellar population synthesis and radiative transfer.« less

Authors:
; ; ;  [1];  [2];  [3];  [4];  [5]; ;  [6];  [7];  [8]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Leiden University, Leiden Observatory, P.O. Box 9513, NL-2300 RA, Leiden (Netherlands)
  3. MPE, Giessenbackstrasse, D-85748 Garching (Germany)
  4. Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States)
  5. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  6. Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)
  7. Kavli Institute for Cosmological Physics, and Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)
  8. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany)
Publication Date:
OSTI Identifier:
21313858
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 700; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/700/1/799; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; COLOR; GALACTIC EVOLUTION; GALAXIES; LUMINOSITY; MASS; PHOTOMETRY; QUASARS; RADIANT HEAT TRANSFER; RED SHIFT; SIMULATION; STARS

Citation Formats

Wuyts, Stijn, Cox, Thomas J., Hayward, Christopher C., Hernquist, Lars, Franx, Marijn, Foerster Schreiber, Natascha M., Hopkins, Philip F., Labbe, Ivo, Marchesini, Danilo, Van Dokkum, Pieter G., Robertson, Brant E., and Toft, Sune. COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS. United States: N. p., 2009. Web. doi:10.1088/0004-637X/700/1/799; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Wuyts, Stijn, Cox, Thomas J., Hayward, Christopher C., Hernquist, Lars, Franx, Marijn, Foerster Schreiber, Natascha M., Hopkins, Philip F., Labbe, Ivo, Marchesini, Danilo, Van Dokkum, Pieter G., Robertson, Brant E., & Toft, Sune. COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS. United States. doi:10.1088/0004-637X/700/1/799; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Wuyts, Stijn, Cox, Thomas J., Hayward, Christopher C., Hernquist, Lars, Franx, Marijn, Foerster Schreiber, Natascha M., Hopkins, Philip F., Labbe, Ivo, Marchesini, Danilo, Van Dokkum, Pieter G., Robertson, Brant E., and Toft, Sune. Mon . "COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS". United States. doi:10.1088/0004-637X/700/1/799; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21313858,
title = {COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS},
author = {Wuyts, Stijn and Cox, Thomas J. and Hayward, Christopher C. and Hernquist, Lars and Franx, Marijn and Foerster Schreiber, Natascha M. and Hopkins, Philip F. and Labbe, Ivo and Marchesini, Danilo and Van Dokkum, Pieter G. and Robertson, Brant E. and Toft, Sune},
abstractNote = {We present a comparison between the observed color distribution, number, and mass density of massive galaxies at 1.5 < z < 3 and a model by Hopkins et al. that relates the quasar and galaxy population on the basis of gas-rich mergers. In order to test the hypothesis that quiescent red galaxies are formed after a gas-rich merger involving quasar activity, we confront photometry of massive (M>4 x 10{sup 10} M{sub sun}) galaxies extracted from the FIRES, GOODS-South, and MUSYC surveys, together spanning an area of 496 arcmin{sup 2}, with synthetic photometry from hydrodynamical merger simulations. As in the Hopkins et al. model, we use the observed quasar luminosity function to estimate the merger rate. We find that the synthetic U - V and V - J colors of galaxies that had a quasar phase in their past match the colors of observed galaxies that are best characterized by a quiescent stellar population. At z {approx} 2.6, the observed number and mass density of quiescent red galaxies with M>4 x 10{sup 10} M{sub sun} is consistent with the model in which every quiescent massive galaxy underwent a quasar phase in the past. At z {approx} 1.9, 2.8 times less quiescent galaxies are observed than predicted by the model as descendants of higher redshift quasars. The merger model also predicts a large number and mass density of galaxies undergoing star formation driven by the merger. We find that the predicted number and mass density accounts for 30%-50% of the observed massive star-forming galaxies. However, their colors do not match those of observed star-forming galaxies. In particular, the colors of dusty red galaxies (accounting for 30%-40% of the massive galaxy population) are not reproduced by the simulations. Several possible origins of this discrepancy are discussed. The observational constraints on the validity of the model are currently limited by cosmic variance and uncertainties in stellar population synthesis and radiative transfer.},
doi = {10.1088/0004-637X/700/1/799; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 700,
place = {United States},
year = {2009},
month = {7}
}