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Title: Significant contribution of the Cerenkov line-like radiation to the broad emission lines of quasars

The Cerenkov line-like radiation in a dense gas (N {sub H} > 10{sup 13} cm{sup –3}) is potentially important in the exploration of the optical broad emission lines of quasars and Seyfert 1 galaxies. With this quasi-line emission mechanism, some long standing puzzles in the study of quasars could be resolved. In this paper, we calculate the power of the Cerenkov line-like radiation in dense gas and compare with the powers of other radiation mechanisms by a fast electron to confirm its importance. From the observed gamma-ray luminosity of 3C 279, we show that the total number of fast electrons is sufficiently high to allow effective operation of the quasi-line emission. We present a model calculation for the luminosity of the Cerenkov Lyα line of 3C 279, which is high enough to compare with observations. We therefore conclude that the broad line of quasars may be a blend of the Cerenkov emission line with the real line produced by the bound-bound transition. A new approach to the absorption of the Cerenkov line is presented with the method of escape probability, which markedly simplifies the computation in the optically thick case. The revised set of formulae for the Cerenkov line-like radiationmore » is more convenient in applications.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Institute of Nuclear, Particle, Astronomy and Cosmology, Department of Physics and Astronomy, and Shanghai Key Lab for Particle Physics and Cosmology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)
  2. Institute of Astronomy and Department of Physics, National Central University, Chung-Li 32054, Taiwan (China)
  3. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn (Germany)
Publication Date:
OSTI Identifier:
22348304
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CHERENKOV RADIATION; COMPARATIVE EVALUATIONS; ELECTRONS; EMISSION; EXPLORATION; GALAXIES; GAMMA RADIATION; LUMINOSITY; OPERATION; PROBABILITY; QUASARS