Poster Presentation
Star formation history of nearby S0 galaxies
Presenter: Qiusheng Gu (Nanjing University)
We present a study of nuclear activities for nearby S0 galaxies. After cross-matching SDSS with the Third Reference Catalog of Bright Galaxies (RC3) and visually checking the SDSS images, we derive a sample of 583 S0 galaxies with the central spectrophotometric information. In order to separate nebular emission lines from the underlying stellar contribution, we fit the stellar population model to the SDSS spectra of these S0 galaxies, and find 8% of S0 galaxies show central star-forming activity and ~10% AGNs, and ~20% LINERs. We also find that star-forming S0s have the lowest stellar masses, over one magnitude lower than the others; and that the active (containing star formation and AGN) S0s locate mainly in the sparse environment, while the normal S0s in the dense environment, which might suggest that the environment play an important role in quenching star formation and/or AGN activities in S0 galaxies. By performing bulge-disk decomposition of star-forming S0s with the 2D fitting software GALFIT, we find that for star-forming S0 galaxies, the bulges are systematically bluer than their disk, and the Sersic index of most star-forming S0s bulges is less than 2, which indicate that the bulges of star-forming S0s might be mainly pseudo-bulges.
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