1. Ultraviolet Properties Early-Type dwarf Galaxies in the Virgo Cluster. Suk Kim and Soo-Chang Rey Astronomy and Space Science, Chungnam National University

2. Motivation UV properties of different morphological Early-Type dwarf galaxies Environmental effects for the UV properties of dwarf elliptical galaxies. We found the dwarf lenticulars and peculiar dwarf ellipticals show distinct locus from that of ordinary dwarf ellipticals in CMR. Early type dwarf galaxies far from the center of the Virgo cluster (r>2 o to the M87; small red circles) shows larger UV fluxes than those near the center of cluster center (r<2 o to the M87; large red circles): These UV bright dwarf galaxies located at outer part of the Virgo cluster are possible candidates showing recent star formation activity.

3. DATA 1.GALEX GR3 : Mosaic Fields of GALEX UV Data 2.SDSS DR5 : u,g,r,i,z Optical Data 3.GOLDMine Data Base

4. Previous Work (Boselli et al. 2007)

5. CMR : Color Magnitude Relation (GALEX UV data and GOLDmine data base ) E : Ellipticals S0 : Lenticulars dE : Dwarf Ellipticals dS0 : Dwarf Lenticulars dE,N : Nucleated dE dEdi : dE with disk dEbc : dE with blue center BCD : Blue Compact Dwarf We found the dwarf lenticulars as well as recently discovered peculiar dwarf ellipticals (with disk and blue center), show distinct locus (yellow rectangulars) from that of ordinary dwarf ellipticals in CMRs. This indicates the UV properties of these dwarf galaxies are different to those of ordinary dwarf ellipticals, suggesting different formation and evolution(e.g., star formation activity).

6. Environmental effect (GALEX UV and SDSS data) Projected spatial distribution of early-type dwarf galaxies matching between GALEX and SDSS within the Virgo cluster Inner circle represents the boundary of the 2 degree radius to the M87. : dE : dS0 : dE,N : dEdi : dEbc : BCD

7. CMR : Color Magnitude Relation (GALEX UV data and SDSS optical data ) : dE : dS0 : dE,N : dEdi : dEbc : BCD Big symbols : Inner galaxies (r < 2 o ) Small symbols : Outer galaxies (r > 2 o ) Outer galaxies bluer

8. Color – Color Relation (GALEX UV data and SDSS optical data ) Big symbols : Inner galaxies (r < 2 o ) Small symbols : Outer galaxies (r > 2 o ) : dE : dS0 : dE,N : dEdi : dEbc : BCD These UV bright dwarf galaxies located at outer part of the Virgo cluster are possible candidates showing recent star formation activity. HαHα HαHα HαHα 1Gyr 5Gyr 10~15 Gyr

9. Conclusion - Ultraviolet properties of early-type dwarf galaxies in the Virgo cluster using the GALEX UV data and SDSS optical data. - Different morphological dwarf galaxies show different UV to optical color magnitude relation(CMRs) - Since dwarf galaxies depend on cluster environments effect, the far from cluster center show larger UV fluxes than those near the center.