Buried AGNs in Advanced Mergers:Mid-infrared color selection as a dual AGN finder

摘要: A direct consequence of hierarchical galaxy formation is the existence dual supermassive black holes (SMBHs), which may be preferentially triggered as active galactic nuclei (AGN) during mergers. Despite decades searching, however, AGNs are extremely rare, and most have been discovered serendipitously. Using all-sky WISE survey, we identified a population over 100 morphologically interacting galaxies or mergers that display red mid-infrared colors often associated in extragalactic sources with powerful AGNs. The vast majority these advanced optically classified star-forming suggesting they represent an obscured cannot found through optical studies. In this work, present Chandra/ACIS observations near-infrared spectra Large Binocular Telescope six projected pair separations less than ~ 10 kpc. combined X-ray, near-infrared, properties provide confirmation four out host at least one AGN, possibly hosting ~10 kpc, despite showing no firm evidence for based on spectroscopic Our results demonstrate 1) studies miss significant fraction single mergers, 2) pre-selection effective identifying AGN candidates late-stage multi-wavelength suggest buried highly absorbed, intrinsic column densities excess N_H >10^24cm^-2, consistent hydrodynamic simulations.