Spectro - Photometric study of star forming early type galaxies

Abstract

We combine the results of optical spectroscopy and photometry of a sample of local early type galaxies by Sloan Digital Sky Survey(SDSS) with spectral energy distribution fitting using the Ultraviolet to midIR photometric data. Among the 50 galaxies from present sample, 39 were found to occupy the position of ”Blue-cloud” and ”Green valley” region in the CMD plane. We compute the parameters such as stellar mass, dust mass, dust luminosity, specific star formation rate and it’s correlation with central black hole mass. This could depict a scenario suggesting ba two way migration of ”Green valley” galaxies, either from SF phase to red sequence or from red sequence to the SF. Specific star formation rate is found to have a strong dependence on the gas content of galaxy over the average stellar age of galaxy population such that younger the stellar population of a galaxy, larger is the gas fraction and hence show high specific star formation rate. This suggests that the star formation in these ETGs may purely of intrinsic origin.