2015ApJ...806...22D

We have completed two years of photometric and spectroscopic monitoring of a large number of active galactic nuclei (AGNs) with very high accretion rates. In this paper, we report on the result of the second phase of the campaign, during 2013-2014, and the measurements of five new Hβ time lags out of eight monitored AGNs. All five objects were identified as super-Eddington accreting massive black holes (SEAMBHs). The highest measured accretion rates for the objects in this campaign are, where, is the mass accretion rates, is the Eddington luminosity and c is the speed of light. We find that the Hβ time lags in SEAMBHs are significantly shorter than those measured in sub-Eddington AGNs, and the deviations increase with increasing accretion rates. Thus, the relationship between broad-line region size () and optical luminosity at 5100 Å,, requires accretion rate as an additional parameter. We propose that much of the effect may be due to the strong anisotropy of the emitted slim-disk radiation. Scaling by the gravitational radius of the black hole (BH), we define a new radius-mass parameter () and show that it saturates at a critical accretion rate of, indicating a transition from thin to slim accretion disk and a saturated luminosity of the slim disks. The parameter is a very useful probe for understanding the various types of accretion onto massive BHs. We briefly comment on implications to the general population of super-Eddington AGNs in the universe and applications to cosmology.