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Paper: The Dust Tori in Palomar-Green Quasars
Volume: 357, The Spitzer Space Telescope: New Views of the Cosmos
Page: 206
Authors: Cao, X.
Abstract: The dust clouds in the torus of a quasar are irradiated by the central source, and the clouds at the inner radius of the torus re-radiate mostly in the near-infrared (NIR) wavebands. The ratio of the NIR luminosity to the bolometric luminosity LNIR/Lbol can therefore reflect the torus geometry to some extent. We estimate the torus opening angles of Palomar-Green(PG) quasars, and find that the opening angle does not evolve with accretion rate. The opening angle is anti-correlated with the black hole mass, which implies that the formation of torus is regulated by the central black hole. The average estimated relative thickness H/R of the tori in the PG quasars is ~ 0.9. The further IR observations on a larger quasar sample including fainter quasars by the Spitzer Space Telescope will help our understanding the physics of the dust tori in quasars.
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