Multicolor Photometry of the Galaxies in the Central Region of Abell 2634

Abstract

An optical photometric observation with the Beijing-Arizona-Taipei-Connecticut multicolor system is carried out for the central region of the nearby cluster of galaxies Abell 2634. From the 2K ? 2K CCD images with 14 filters, which cover a range of wavelength from 3600 to 10000 ?, 5572 sources are detected down to V ~ 20 mag in a field of 56' ? 56' centered on this regular cluster of galaxies. As a result, we achieved the spectral energy distributions (SEDs) of all sources detected. There are 178 previously known galaxies included in our observations, 147 of which have known radial velocities in the literature. After excluding the foreground and background galaxies, a sample of 124 known members is formed for an investigation of the SED properties. The comparison of observed SEDs of the early-type member galaxies with the template SEDs demonstrates the accuracy and reliability of our photometric measurements. Based on the knowledge of SED properties of member galaxies, we performed the selection of faint galaxies belonging to Abell 2634. It is well shown that the color-color diagrams are powerful in the star-galaxy separation. As a result, 359 faint galaxies are selected by their color features. The technique of photometric redshift and color-magnitude correlation for the early-type galaxies are applied for these faint galaxies, and a list of 74 faint member galaxies is achieved. On the basis of the newly generated sample of member galaxies, the spatial distribution and color-magnitude relation of the galaxies in the core region of Abell 2634 are discussed. There exists a tendency that the color index dispersion of the early-type members is larger for the outer region, which might reflect some clues about the environmental effect on the evolution of galaxies in a cluster.