The disk-wind scenario for the broad-line region (BLR) and toroidal obscuration in active galactic nuclei (AGNs) predicts the disappearance of the BLR at low luminosities. In accordance with the model predictions, data from a nearly complete sample of nearby AGNs show that the BLR disappears at luminosities lower than 5 × 1039(M/107 M⊙)2/3 erg s-1, where M is the black hole mass. The radiative efficiency of accretion onto the black hole is ≲10-3 for these sources, indicating that their accretion is advection-dominated.
Digital Object Identifier (DOI)
Elitzur, Moshe and Ho, Luis C., "On the Disappearance of the Broad-Line Region in Low-Luminosity Active Galactic Nuclei" (2010). Physics and Astronomy Faculty Publications. 195.