The ACS Fornax Cluster Survey. IX. The color-magnitude relation of globular cluster systems

Mieske, Steffen, Jordán, Andrés, Côté, Patrick, Peng, Eric W., Ferrarese, Laura, Blakeslee, John P., Mei, Simona, Baumgardt, Holger, Tonry, John L., Infante, Leopoldo and West, Michael J. (2010) The ACS Fornax Cluster Survey. IX. The color-magnitude relation of globular cluster systems. The Astrophysical Journal, 710 2: 1672-1682. doi:10.1088/0004-637X/710/2/1672

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Author Mieske, Steffen
Jordán, Andrés
Côté, Patrick
Peng, Eric W.
Ferrarese, Laura
Blakeslee, John P.
Mei, Simona
Baumgardt, Holger
Tonry, John L.
Infante, Leopoldo
West, Michael J.
Title The ACS Fornax Cluster Survey. IX. The color-magnitude relation of globular cluster systems
Journal name The Astrophysical Journal   Check publisher's open access policy
ISSN 0004-637X
Publication date 2010-02-20
Sub-type Article (original research)
DOI 10.1088/0004-637X/710/2/1672
Open Access Status File (Publisher version)
Volume 710
Issue 2
Start page 1672
End page 1682
Total pages 11
Place of publication Philadelphia, PA, United States
Publisher Institute of Physics Publishing
Collection year 2011
Language eng
Formatted abstract
We investigate the color-magnitude relation for globular clusters (GCs) - the so-called blue tilt - detected in the Advanced Camera for Surveys (ACS) Fornax Cluster Survey and using the combined sample of GCs from the ACS Fornax and Virgo Cluster Surveys. We find a tilt of γzd(g - z)/dz = -0.0257±0.0050 for the full GC sample of the Fornax Cluster Survey (5800 GCs). This is slightly shallower than the value γz = -0.0459±0.0048 found for the Virgo Cluster Survey GC sample (11,100 GCs). The slope for the merged Fornax and Virgo data sets (16,900GCs) is γz = -0.0293±0.0085, corresponding to a mass-metallicity relation of Z ∝ M 0.43±0.12. We find that the blue tilt sets in at masses in excess of M ~ 2 × 105 M. The tilt is stronger for GCs belonging to high-mass galaxies (M ≳ 5 × 1010 M) than for those in low-mass galaxies (M * ≲ 5 × 1010 M ·). It is also more pronounced for GCs with smaller galactocentric distances. Our findings suggest a range of mass-metallicity relations ZGC ∝ M GC 0.3-0.7 which vary as a function of host galaxy mass/luminosity, a scaling similar to that observed for dwarf spheroidal galaxies. We compare our observations to a recent model of star cluster self-enrichment with generally favorable results. We suggest that, within the context of this model, the protocluster clouds out of which the GCs formed may have had density profiles slightly steeper than isothermal and/or star formation efficiencies somewhat below 0.3. We caution, however, that the significantly different appearance of the color-magnitude diagrams (CMDs) defined by the GC systems associated with galaxies of similar mass and morphological type poses a challenge to any single mechanism, including self-enrichment, that seeks to explain generically the observed GC color-magnitude relations. We therefore suggest that the detailed (and stochastic) merger/accretion histories of individual galaxies have likely played a non-negligible role determining the distribution of GCs in the CMDs of individual GC systems.
© 2010. The American Astronomical Society. All rights reserved.
Keyword Galaxies
Individual (Fornax, Virgo)
Fundamental parameters
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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Citation counts: TR Web of Science Citation Count  Cited 40 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 41 times in Scopus Article | Citations
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Created: Tue, 22 Feb 2011, 15:19:25 EST by Dr Holger Baumgardt on behalf of Physics