Type 2 AGN Host Galaxies in the Chandra-COSMOS Legacy Survey: No Evidence of AGN-driven Quenching

Abstract

Abstract We investigate the star formation properties of a large sample of ∼2300 X-ray-selected Type 2 Active Galactic Nuclei (AGNs) host galaxies out to in the Chandra COSMOS Legacy Survey in order to understand the connection between the star formation and nuclear activity. Making use of the existing multi-wavelength photometric data available in the COSMOS field, we perform a multi-component modeling from far-infrared to near-ultraviolet using a nuclear dust torus model, a stellar population model and a starburst model of the spectral energy distributions (SEDs). Through detailed analyses of SEDs, we derive the stellar masses and the star formation rates (SFRs) of Type 2 AGN host galaxies. The stellar mass of our sample is in the range of with uncertainties of ∼0.19 dex. We find that Type 2 AGN host galaxies have, on average, similar SFRs compared to the normal star-forming galaxies with similar M stellar and redshift ranges, suggesting no significant evidence for enhancement or quenching of star formation. This could be interpreted in a scenario, where the relative massive galaxies have already experienced substantial growth at higher redshift ( ), and grow slowly through secular fueling processes hosting moderate-luminosity AGNs.