Author(s): , , ,
Institution(s): 1. Korea Astronomy and Space Science Institute, 2. Korea Institute for Advanced Study, 3. Seoul National University
We present a stellar population analysis of early-type galaxies with recent star formation in the SDSS-GALEX-WISE galaxy catalog. We stack the optical spectra of early-type galaxies with different amounts of mid-infrared and near-ultraviolet excess emissions to measure spectral features and derive the star formation histories. The WISE [3.4]- and NUV-r colors show good correlations with the strength of spectral features including the 4000 angstrom break and equivalent widths of Balmer lines. The star formation history derived from the fit of the spectra with STARLIGHT shows that the early-type galaxies with mid-infrared and/or near-ultraviolet excess have more young populations than quiescent early-type galaxies. These results support the idea that the early-type galaxies with mid-infrared and/or near-ultraviolet excess have experienced recent star formation within 1-2 Gyrs.