The Hunt for Red Dual AGNs I: Spatially-Resolved Mid-IR Dual AGNs in the DeCam Legacy Survey

Theoretical studies predict that dual AGNs are a critical stage of galaxy merger-driven supermassive black hole growth. Systematic searches for dual AGNs typically target late-stage mergers (≤10 kpc nuclear separations) and select AGNs based on optical diagnostics. Yet, simulations predict that obscuration can occur early in the merger sequence, and that a significant fraction of dual AGNs can be found beyond 10 kpc. Here, we report on a new sample of 157 spatially resolved mid-IR dual AGNs candidates selected based upon their mid-IR W1-W2 colors from the Wide-Field Infrared Survey Explorer and optically classified as galaxy merger candidates using imaging from the Dark Energy Camera Legacy Survey. Spectroscopic results are presented for approximately 2/3 of the sample. 76 candidates have been confirmed to reside in galaxy mergers; among these, 13 have been confirmed as bona fide mid-IR dual AGNs, while 63 represent strong dual AGN candidates that require further examination. 46 candidates have been rejected as non-merger contaminants (foreground-background AGNs, separations inconsistent with interacting galaxies, etc.). 35 candidates still await spectroscopic coverage. The confirmed and high confidence dual AGN candidates exhibit separations of 14.5-129 kpc; >50