A novel black hole mass scaling relation based on coronal gas, and its dependence with the accretion disc

Using bona-fide black hole (BH) mass estimates from reverberation mapping and the line ratio [Si VI] 1.963 mu m/Br gamma(broad) as tracer of the AGN ionizing continuum, a novel BH-mass scaling relation of the form log(M-BH) = (6.40 +/- 0.17) - (1.99 +/- 0.37) x log ([Si VI]/Br gamma(broad)), dispersion 0.47 dex, over the BH mass interval, 10(6)-10(8) M-circle dot is found. Following on the geometrically thin accretion disc approximation and after surveying a basic parameter space for coronal lines production, we believe one of main drivers of the relation is the effective temperature of the disc, which is effectively sampled by the [Si VI] 1.963 mu m coronal line for the range of BH masses considered. By means of CLOUDY photoionization models, the observed anticorrelation appears to be formally in line with the thin disc prediction T-di(sc) proportional to M-BH(-1/4).

Automated summary

A novel black hole mass scaling relation has been discovered, with the effective temperature of the disc being identified as one of the main drivers of this relationship. This relation is valid over the BH mass interval of 10^6-10^8 M☉.