Abstract:
Ultra-luminous infrared galaxies (ULIRGs, with infrared luminosity, L_IR > 1E12 Lsun) are a population of the most intensely star-forming galaxies in the local universe, with star formation rates (SFR) of 100-1000 Msun/yr. They are thought to represent rapidly growing phase of massive galaxies before quenching of their star formation by the feedback effect of stellar wind and/or AGN outflow. Therefore ULIRGs are a unique population to understand the growth of supermassive blackholes (SMBH) and their host galaxies. In order to perform a detailed study on the relationship of star formation and AGN activities, we constructed a statistically complete ULIRG sample by cross-matching the FIR catalog of AKARI and Herschel with the SDSS optical spectroscopic and WISE MIR photometric data . The sample consists of approximately 1000 ULIRGs at z=0.1-1.0, which covers a large AGN fraction from ~ 0 to 50%, and is one of the largest ULIRG catalog. A spectra-SED simultaneous fitting method is developed to analyze the evolving-time and the AGN's contribution in these galaxies. This study can be helpful to statistically understand the evolution of massive galaxies during their mostly active epoch.