TY - JOUR
T1 - Extragalactic globular clusters in the near infrared III. NGC 5846 and NGC 7192
T2 - Quantifying the age distribution of sub-populations
AU - Hempel, M.
AU - Hilker, M.
AU - Kissler-Patig, M.
AU - Puzia, T. H.
AU - Minniti, D.
AU - Goudfrooij, P.
PY - 2003/7
Y1 - 2003/7
N2 - 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)blue = 2.57 ± 0.06 and (V - K)red = 3.18 ± 0.06. 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.
AB - 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)blue = 2.57 ± 0.06 and (V - K)red = 3.18 ± 0.06. 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.
KW - Galaxies: individual: NGC 5846, NGC 7192
KW - Galaxies: star clusters
UR - http://www.scopus.com/inward/record.url?scp=0038045720&partnerID=8YFLogxK
U2 - 10.1051/0004-6361:20030598
DO - 10.1051/0004-6361:20030598
M3 - Article
AN - SCOPUS:0038045720
VL - 405
SP - 487
EP - 497
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 2
ER -