| Abstract: | In simulations, major encounters between gas-rich galaxies are predicted to drive gas to the centers of interacting and merging systems triggering new star formation (SF) and fueling an active galactic nucleus (AGN). Depending on the rate of SF, large amounts of obscuring dust can make detection of merger-induced activity difficult and may be at the heart of the ongoing merger-AGN connection debate. To provide better constraints on the importance of obscured AGNs, we use data from the Wide-field Infrared Survey Explorer (WISE) for a comprehensive sample of over 1000 major galaxy interactions and ongoing mergers visually selected from the SDSS with Mstar > 1e10 Msun and 0.01 < z < 0.08. We examine the [3.4]-[4.6] versus [4.6]-[12] micron color-color plane and find that most interactions and mergers have the same colors as 'normal' (non-interacting and non-merging) galaxies, which define a narrow [3.4]-[4.6] micron locus and span a wide range in [4.6]-[12] micron colors from spectroscopically quiescent (blue, no dust) to galaxies with SF emission (dust-reddened). We find that 2 - 9% of mergers (and 1.0 - 2.5% of interactions) have unusually red [3.4]-[4.6] micron colors, which are associated with dust-obscured (Type-2) AGNs. We note that mergers (interactions) are 5 - 20 (3 - 5) times more likely to host a buried AGN than normal galaxies. This increased likelihood of dusty AGN activity in mergers and interactions supports an AGN-merger connection. We also find that optical emission-line AGNs (Seyferts) identified as mergers are 2 - 6 times more likely to be obscured than are non-merging Seyferts. We investigate the nature of merging and interacting galaxies with dusty AGN. Using SDSS urz colors to distinguish quiescent from star-forming galaxies, we find that more than three-quarters of this subpopulation are forming stars. We further examine stellar masses, mass ratios, pair separations, [OIII] luminosity, and environments and find that this subpopulation is not statistically different from those of the bulk of mergers and interactions with normal WISE colors. Our findings indicate a strong association between ongoing star formation and dust-enshrouded black hole growth in merging galaxies as predicted in the modern merger hypothesis. |