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Extragalactic Globular Clusters in the Near Infrared: III. NGC 5846 and NGC 7192

Maren Hempel·Michael Hilker·Markus Kissler-Patig·Thomas H. Puzia·Dante Minniti·Paul Goudfrooij
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Abstract

In this third paper of our series on near-IR and optical photometry of globular cluster systems in early-type galaxies we concentrate on the photometric results for NGC 5846 and NGC 7192, two group ellipticals, and on a first comparison between the globular cluster systems investigated so far. In NGC 5846 the colour-colour diagram shows clear bi-modality in (V-K), which is confirmed by a KMM test. The mean colour of both peaks were estimated to be (V-K) =2.57+/-0.06 (blue) and (V-K)=3.18+/-0.06 (red). The situation in NGC 7192 is different, in that the colour-colour diagram gives no evidence for a distinct second population of globular clusters. Using simulated colour distributions of globular cluster systems, we make a first step in quantifying the cumulative age distribution in globular cluster systems. Also here the result for NGC 5846 leads us to the conclusion that its metal-rich globular cluster population contains two globular cluster populations which differ in age by several Gyr. The age structure for NGC 7192 shows instead strong similarity with a single-age population.

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Maren Hempel, Michael Hilker, Markus Kissler-Patig, Thomas H. Puzia, Dante Minniti, Paul Goudfrooij. 2003-04-25. Extragalactic Globular Clusters in the Near Infrared: III. NGC 5846 and NGC 7192. https://doi.org/10.1051/0004-6361%3A20030598

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