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Article
Globular cluster populations : first results from S4G early-type galaxies.
Faculty Scholarship
  • Dennis Zaritsky, University of Arizona
  • Manuel Aravena, Universidad Diego Portales
  • E. Athanassoula, Aix Marseille Universite
  • Albert Bosma, Aix Marseille Universite
  • Sebastien Comeron, University of Oulu
  • Bruce G. Elmegreen, T. J. Watson Research Center
  • Santiago Erroz-Ferrer, Instituto de Astrofísica de Canarias
  • Dimitri A. Gadotti, European Southern Observatory
  • Joannah Hinz, MMT Observatory
  • Luis C. Ho, Peking University
  • Benne W. Holwerda, University of Louisville
  • Johan H. Knapen, Universidad de La Laguna
  • Jarkko Laine, University of Oulu
  • Eija Laurikainen, University of Oulu
  • Juan Carlos Munoz-Mateos, European Southern Observatory
  • Heikki Salo, University of Oulu
  • Kartik Sheth, National Radio Astronomy Observatory
Document Type
Article
Publication Date
2-1-2015
Department
Physics and Astronomy
Abstract

Using 3.6μm images of 97 early-type galaxies, we develop and verify methodology to measure globular cluster populations from the S4G survey images. We find that (1) the ratio, TN, of the number of clusters, NCL, to parent galaxy stellar mass, M∗, rises weakly with M∗ for early-type galaxies with M∗ > 1010 M when we calculate galaxy masses using a universal stellar initial mass function (IMF) but that the dependence of TN on M∗ is removed entirely once we correct for the recently uncovered systematic variation of IMF with M∗; and (2) for M∗ < 1010 M, there is no trend between NCL and M∗, the scatter in TN is significantly larger (approaching two orders of magnitude), and there is evidence to support a previous, independent suggestion of two families of galaxies. The behavior of NCL in the lower-mass systems is more difficult to measure because these systems are inherently cluster-poor, but our results may add to previous evidence that large variations in cluster formation and destruction efficiencies are to be found among low-mass galaxies. The average fraction of stellar mass in clusters is ∼0.0014 for M∗ > 1010 M and can be as large as ∼0.02 for less massive galaxies. These are the first results from the S4G sample of galaxies and will be enhanced by the sample of early-type galaxies now being added to S4G and complemented by the study of later-type galaxies within S4G.

Comments

Copyright 2015. The American Astronomical Society. All rights reserved.

http://dx.doi.org/10.1088/0004-637X/799/2/159

DOI
10.1088/0004-637X/799/2/159
Citation Information

Zaritsky, Dennis, et al. "Globular Cluster Populations: First Results from S4G Early-Type Galaxies." 2015. The Astrophysical Journal 799(2): 19 pp.