Carbon star survey of Local Group galaxies^*

IX. The spheroidal galaxy NGC 185

¹ INAF, Osservatorio Astronomico di Roma, Viale del Parco Mellini 84, 00136 Roma, Italia
² Département de Physique, Université de Montréal, CP 6128, Succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada e-mail: demers@astro.umontreal.ca

Corresponding author: P. Battinelli, battinel@oarhp1.rm.astro.it

Received: 2 September 2003
Accepted: 15 December 2003

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 , corresponding to , 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, , demonstrating that the intermediate-age population of NGC 185 is more concentrated than its old population. A tidal radius, is determined from red giant star counts. The C/M ratio of NGC 185 is 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.