| Abstract | We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume that consists mostly of young stellar populations and a well-defined red giant branch (RGB). The tip of the RGB is found to be at I_TRGB=22.65+/-0.10 mag. From this, the distance to this galaxy is estimated to be d=2.08+/-0.12 Mpc. The corresponding distance of this galaxy from the center of the Local Group is 1.92 Mpc, showing that it is located outside the Local Group. The large distance, combined with its velocity information, indicates that it is very likely a member of the Sculptor Group. The mean metallicity of the RGB is estimated to be [Fe/H]=-1.98+/-0.17 dex. The total magnitudes of UKS 2323-326 (_BSG=20.33+/-0.25, <(B-V)(3)>_BSG=0.14+/-0.07, _RSG=20.74+/-0.18, and <(B-V)(3)>_RSG=1.35+/-0.08 mag. The corresponding absolute magnitudes are derived to be _BSG=-6.31 and _RSG=-5.91 mag, which are about a half-magnitude fainter than those expected from conventional correlations with galaxy luminosity. |
