Carbon star survey in the local group. VI. The dwarf spheroidal galaxy NGC 205

We present a CFH12K survey of the carbon stars in NGC 205 and its surrounding field. We find that the number of C stars in NGC 205 is low (similar to500) for its luminosity and that very few C stars are seen outside of the 10' isophote, suggesting tidal stripping by M31. Their = -4.54, a magnitude nearly identical to what has been found in other galaxies with numerous C stars. Stars with accurate (R-I) photometry, to Iapproximate to22.5, are used to determine the outer profile of NGC 205. A King profile with r(t)=19.'77+/-3.'00 fits the data for distances larger than 7'. This r(t) implies that NGC 205 reached a minimum distance to M31 of similar to42 kpc. The spatial distribution of C stars in the surrounding field reveals that some C stars belong to to the disk of M31, seen in projection, and that a surplus of C stars seen west of NGC 205 could be part of tidal debris left along its orbit. Finally, we report evidence of a transient period of enhanced star formation that occurred 1-2 Gyr ago in the northwest half of NGC 205.