Apart from viewing-dependent obscuration, intrinsic broad-line emission from active galactic nuclei (AGN) follows an evolutionary sequence: type 1 → 1.2/1.5 → 1.8/1.9 → 2 as the accretion rate on to the central black hole is decreasing. This spectral evolution is controlled, at least in part, by the parameter Lbol/M2/3, where Lbol is the AGN bolometric luminosity and M is the black hole mass. Both this dependence and the double-peaked profiles that emerge along the sequence arise naturally in the disc-wind scenario for the AGN broad-line region.

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Published in Monthly Notices of the Royal Astronomical Society, v. 438, issue 4, p. 3340-3351.

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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