We present a photometric study of galaxies in the central regions of six nearby galaxy clusters at redshift z=0.0231~0.0951. We have derived BVI photometry of the galaxies from the CCD images obtained at the Bohyunsan Optical Astronomical Observatory (BOAO) in Korea, and JHKs photometry of the bright galaxies from the 2MASS extended source catalog. Comparing the galaxy photometry results with the simple stellar population model of Bruzual & Charlot (2003) in the optical & NIR color-color diagrams, we have estimated the ages and metallicities of early type galaxies. We have found that the observed galaxies had recent star-formation mostly 5 ~ 7 Gyrs ago but the spread in age estimation is rather large. The average metallicities are [Fe/H]=0.l~0.5 dex. These results support the hypothesis that large early type galaxies in clusters are formed via hierarchical merging of smaller galaxies.

• TAEHYUN KIM(Astronomy Program, SEES, Seoul National University)
• MYUNG GYOON LEE(Astronomy Program, SEES, Seoul National University)