Volume 525, January 2011
|Number of page(s)||16|
|Section||Catalogs and data|
|Published online||26 November 2010|
An optical/NIR survey of globular clusters in early-type galaxies
I. Introduction and data reduction procedures⋆
Astronomical Institute, University of Utrecht,
2 Department of Physics and Astronomy, McMaster University, Hamilton L8S 4M1, Canada
3 Space Telescope European Coordinating Facility, European Southern Observatory, Garching, Germany
4 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
5 UCO/Lick Observatory, University of California, Santa Cruz, CA 95064, USA
Accepted: 1 October 2010
Context. The combination of optical and near-infrared (NIR) colours has the potential to break the age/metallicity degeneracy and offers a better metallicity sensitivity than optical colours alone. Previous tudies of extragalactic globular clusters (GCs) with this colour combination, however, have suffered from small samples or have been restricted to a few galaxies.
Aims. We compile a homogeneous and representative sample of GC systems with multi-band photometry to be used in subsequent papers where ages and metallicity distributions will be studied.
Methods. We acquired deep K-band images of 14 bright nearby early-type galaxies. The images were obtained with the LIRIS near-infrared spectrograph and imager at the William Herschel Telescope (WHT) and combined with optical ACS g and z images from the Hubble Space Telescope public archive.
Results. For the first time we present homogeneous GC photometry in this wavelength regime for a large sample of galaxies, 14. We achieved a limiting magnitude of K ~ 20−21. For the majority of the galaxies we detect about 70 GCs each. NGC 4486 and NGC 4649, the cluster-richest galaxies in the sample contain 301 and 167 GCs, respectively. We present tables containing coordinates, photometry and sizes of the GCs.
Key words: galaxies: elliptical and lenticular, cD / galaxies: evolution / galaxies: star clusters: general
Full Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/525/A19
© ESO, 2010
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