Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical galaxy NGC 147

Near-infrared J, H and K' images were used to investigate the stellar contents of the asymptotic giant branch (AGB) population in the nearby dwarf elliptical galaxy NGC 147. The obtained (K, J-K) and (K, H-K) color-magnitude diagrams contain stars of AGB and red giant branch populations, where the former consists of a group of bright blue stars, a dominant population of M giant and a red C star population. We identified 91 AGB C stars in NGC 147 with the mean absolute magnitude and colors of <M_K> = -7.56, = 1.81 and = 0.74. The estimated number ratio of C stars to M giant stars (C/M) is 0.16±0.02. The estimated local C/M ratios of 0.14± 0.02 for the inner region (r70'') indicate a weak radial gradient. The mean bolometric magnitude of 91 C stars in NGC 147 is <M_bol> = -4.32± 0.49. The bolometric luminosity function of M giant stars in NGC 147 extends up to M_bol = -5.8 mag, and that of only C stars spans -5.6