Seeking Multiwavelength Signs of Slim-Disk Accretion in Narrow-Line Seyfert 1 Galaxies

To understand how supermassive black holes may have grown through episodes of near/super-Eddington accretion, we need observational constraints on how such episodes affect the physics of AGN central engines. At Eddington ratios above ∼30%, the accretion disk is believed to transition at small radii into a geometrically thick and radiatively inefficient 'slim' disk state, altering the appearance and output of the central engine. NLS1 galaxies appear to be young, high-Eddington AGNs with extreme properties, offering unique and critical opportunities to examine slim-disk accretion. Here, I summarize observational support we have found for slim-disk accretion in nearby samples of both supermassive and intermediate-mass AGNs via tests across radio, optical, ultraviolet, and X-ray bands. I explore applying our results to NLS1 populations and discuss some future prospects to learn how much accretion power may be advected directly into the black hole vs. radiated away or ejected by outflows.