Carbon star survey of Local Group galaxies. IX. The spheroidal galaxy NGC 185
Abstract
We used the CFH12K wide field camera to survey the carbon star population of NGC 185 using the CN-TiO technique. 145 C stars are identified with a mean < I > = 19.99±0.05, corresponding to < MI> = -4.41±0.05, a mean luminosity similar to what was recently found for the C star population of NGC 147. The stellar surface density profile of NGC 185 follows a power law with an exponential scale length of 2.53 ± 0.07'. The surface density of C stars follows also a power law but with a smaller scale length, 1.56 ± 0.06, demonstrating that the intermediate-age population of NGC 185 is more concentrated than its old population. A tidal radius, rt = 22.5±2.2' is determined from red giant star counts. The C/M ratio of NGC 185 is 0.17 ± 0.02 with no apparent sign of a radial gradient. We compare the carbon star populations of NGC 185 and NGC 147 to conclude that it is unlikely that they form a close pair.
Based on observations carried out at the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii.- Publication:
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Astronomy and Astrophysics
- Pub Date:
- April 2004
- DOI:
- 10.1051/0004-6361:20034272
- Bibcode:
- 2004A&A...417..479B
- Keywords:
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- galaxies: individual: NGC 185;
- galaxies: stellar content;
- galaxies: structure