UBRI photometry of globular clusters in the Leo group galaxy NGC 3379期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

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UBRI photometry of globular clusters in the Leo group galaxy NGC 3379

Authors:	Shannon Whitlock Duncan A Forbes Michael A Beasley

Institution:	Centre for Astrophysics &Supercomputing, Swinburne University, Hawthorn, VIC 3122, Australia

Abstract:	We present wide-area UBRI photometry for globular clusters around the Leo group galaxy NGC 3379. Globular cluster candidates are selected from their B -band magnitudes and their ( U − B )_o versus ( B − I )_o colours. A colour–colour selection region was defined from photometry of the Milky Way and M31 globular cluster systems. We detect 133 globular cluster candidates, which supports previous claims of a low specific frequency for NGC 3379. The Milky Way and M31 reveal blue and red subpopulations, with ( U − B )_o and ( B − I )_o colours indicating mean metallicities similar to those expected based on previous spectroscopic work. The stellar population models of Maraston and Brocato et al. are consistent with both subpopulations being old, and with metallicities of Fe/H]∼−1.5 and −0.6 for the blue and red subpopulations, respectively. The models of Worthey do not reproduce the ( U − B )_o colours of the red (metal-rich) subpopulation for any modelled age. For NGC 3379 we detect a blue subpopulation with similar colours, and presumably age/metallicity, to that of the Milky Way and M31 globular cluster systems. The red subpopulation is less well defined, perhaps due to increased photometric errors, but indicates a mean metallicity of Fe/H]∼−0.6.

Keywords:	globular clusters: general galaxies: individual: NGC 3379 galaxies: star clusters

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