Poster Presentation

Effects of Galaxy Environments on Star Formation Activities

Hsuan-Ju Chen (IANCU), Chorng-Yuan Hwang (IANCU)

Activities of star formation dominate the evolution of galaxies. Elliptical galaxies are believed to be old galaxies in the Hubble sequence, which might have no star formation activities. On the other hand, spiral galaxies are believed to be young galaxies abounding with gas and dust. With the Sloan Digital Sky Survey (SDSS) and the Galaxy Zoo, we selected a sample of morphologically-identified elliptical and spiral galaxies and considered their mid-infrared (MIR) emission as indices of their star formation rates. We found some nearby elliptical galaxies with very strong MIR emission and some spiral galaxies with very low MIR emission. We probed the causes of the unexpected star formation activities by investigating the connection of the star formation rates and the environments of these galaxies in different redshifts. We display our preliminary results and discuss their implication on the evolution of galaxies in this poster.