The Importance of Major Mergers in the Build Up of Stellar Mass in Brightest Cluster Galaxies at z = 1

Authors

C. Lidman, Australian Astronomical Observatory, Australia
G. Iacobuta, Australian Astronomical Observatory, Australia
A. E. Bauer, Australian Astronomical Observatory, Australia
L. F. Barrientos, Pontifica Universidad Cathólica de Chile, Chile
P. Cerulo, Swinburne University of Technology, Australia
W. J. Couch, Swinburne University of Technology, Australia
L. Delaye, Observatoire de Paris, France
R. Demarco, Universidad de Concepcion, Chile
E. Ellingson, University of Colorado
A. J. Faloon, McGill University, Canada
D. Gilbank, South African Astronomical Observatory, South Africa
M. Huertas-Company, Observatoire de Paris, France
S. Mei, Observatoire de Paris, France
J. Meyers, Stanford University
A. Muzzin, Leiden University, Netherlands
A. Noble, McGill University, Canada
J. Nantais, Universidad de Concepcion, Chile
A. Rettura, Jet Propulsion Laboratory
P. Rosati, Swinburne University of Technology, Australia
R. Sánchez-Janssen, European Southern Observatory, Chile
V. Strazzullo, Universit Paris Diderot, France
T. M. A. Webb, McGill University, Canada
G. Wilson, University of California - Riverside
Renbin Yan, University of KentuckyFollow
H. K. C. Yee, University of Toronto, Canada

Abstract

Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) have increased their stellar mass by a factor of almost 2 between z ∼ 0.9 and z ∼ 0.2. The numerical simulations further suggest that more than half this mass is accreted through major mergers. Using a sample of 18 distant galaxy clusters with over 600 spectroscopically confirmed cluster members between them, we search for observational evidence that major mergers do play a significant role. We find a major merger rate of 0.38 ± 0.14 mergers per Gyr at z ∼ 1. While the uncertainties, which stem from the small size of our sample, are relatively large, our rate is consistent with the results that are derived from numerical simulations. If we assume that this rate continues to the present day and that half of the mass of the companion is accreted on to the BCG during these mergers, then we find that this rate can explain the growth in the stellar mass of the BCGs that is observed and predicted by simulations. Major mergers therefore appear to be playing an important role, perhaps even the dominant one, in the build up of stellar mass in these extraordinary galaxies.

Document Type

Article

Publication Date

7-21-2013

Notes/Citation Information

Published in Monthly Notices of the Royal Astronomical Society, v. 433, issue 1, p. 825-837.

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

The copyright holder has granted the permission for posting the article here.

Digital Object Identifier (DOI)

http://dx.doi.org/10.1093/mnras/stt777

Repository Citation

Lidman, C.; Iacobuta, G.; Bauer, A. E.; Barrientos, L. F.; Cerulo, P.; Couch, W. J.; Delaye, L.; Demarco, R.; Ellingson, E.; Faloon, A. J.; Gilbank, D.; Huertas-Company, M.; Mei, S.; Meyers, J.; Muzzin, A.; Noble, A.; Nantais, J.; Rettura, A.; Rosati, P.; Sánchez-Janssen, R.; Strazzullo, V.; Webb, T. M. A.; Wilson, G.; Yan, Renbin; and Yee, H. K. C., "The Importance of Major Mergers in the Build Up of Stellar Mass in Brightest Cluster Galaxies at z = 1" (2013). Physics and Astronomy Faculty Publications. 9.
https://uknowledge.uky.edu/physastron_facpub/9