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Title: THE BROAD LINE REGION IN NGC 4051: AN INFLOW ILLUMINATED BY A 10{sup 5} K ACCRETION DISK

Adopting a spherically symmetric steady-state ballistic inflow as the kinematic model for the gas distribution responsible for producing the H{alpha} emission line, and a central black hole (BH) mass of 1.7 Multiplication-Sign 10{sup 6} M{sub Sun} determined from prior reverberation mapping, leads to the following dimensions for the size of the broad line region (BLR) in NGC 4051; an inner radius {approx}3 lt-day and a lower limit to the outer radius {approx}475 lt-day. Thus, the previously determined reverberation size for the BLR marks just the inner radius of a much larger volume of ionized gas. The number of ionizing photons required to sustain the H{alpha} emission line luminosity exceeds the number observed to be available from the central active galactic nucleus (AGN) by a factor of 3-4. Such a large ionizing deficit can be reconciled if the BLR is ionized by a 10{sup 5} K accretion disk that is hidden from direct view by the high opacity of intervening H gas. A new definition is introduced for the ionization parameter that acknowledges the fact that H opacity significantly attenuates the flux of ionizing photons in the large, partially ionized nebula surrounding the AGN. Collectively, the results have important implications formore » BH masses estimated using reverberation radii and the structure of the BLR inferred from velocity-delay maps.« less
Authors:
;  [1]
  1. Department of Physics, Embry-Riddle Aeronautical University, Prescott, AZ 86301 (United States)
Publication Date:
OSTI Identifier:
22131017
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BALMER LINES; BLACK HOLES; COSMIC NUCLEI; EMISSION; LUMINOSITY; OPACITY; PHOTONS; SPHERICAL CONFIGURATION; STEADY-STATE CONDITIONS; SYMMETRY