Bibcode
Zaritsky, D.; Aravena, Manuel; Athanassoula, E.; Bosma, Albert; Comerón, Sébastien; Elmegreen, Bruce G.; Erroz-Ferrer, S.; Gadotti, Dimitri A.; Hinz, Joannah L.; Ho, Luis C.; Holwerda, Benne; Knapen, J. H.; Laine, Jarkko; Laurikainen, Eija; Muñoz-Mateos, Juan Carlos; Salo, Heikki; Sheth, Kartik
Bibliographical reference
The Astrophysical Journal, Volume 799, Issue 2, article id. 159, 19 pp. (2015).
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2
2015
Journal
Citations
12
Refereed citations
11
Description
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.
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