Globular cluster populations: First results from S4G early-type galaxies

Dennis Zaritsky, Manuel Aravena, E. Athanassoula, Albert Bosma, Sébastien Comerón, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne Holwerda, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Juan Carlos Muñoz-Mateos, Heikki Salo, Kartik Sheth

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Using 3.6 μm 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, T N, of the number of clusters, N CL, 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 T N 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 N CL and M, the scatter in T N 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 N CL 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.

Original languageEnglish (US)
Article number159
JournalAstrophysical Journal
Volume799
Issue number2
DOIs
StatePublished - Feb 1 2015

Keywords

  • galaxies: evolution
  • galaxies: formation
  • galaxies: star clusters: general
  • galaxies: stellar content

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Zaritsky, D., Aravena, M., Athanassoula, E., Bosma, A., Comerón, S., Elmegreen, B. G., Erroz-Ferrer, S., Gadotti, D. A., Hinz, J. L., Ho, L. C., Holwerda, B., Knapen, J. H., Laine, J., Laurikainen, E., Muñoz-Mateos, J. C., Salo, H., & Sheth, K. (2015). Globular cluster populations: First results from S4G early-type galaxies. Astrophysical Journal, 799(2), [159]. https://doi.org/10.1088/0004-637X/799/2/159