PHYSICAL PROPERTIES OF LUMINOUS DUST-POOR QUASARS
PHYSICAL PROPERTIES OF LUMINOUS DUST-POOR QUASARS
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DOI：
10.1088/0004-637x/779/2/104
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发表时间：
2013-10
期刊：
影响因子：
--
通讯作者：
H. Jun;M. Im
中科院分区：
文献类型：
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作者：
H. Jun;M. Im
We identify and characterize a population of luminous, dust-poor quasars at 0 6. This class of active galactic nuclei is known to show little IR emission from dusty structure, but it is poorly understood in terms of number evolution and dependence on physical quantities. To better understand the properties of these quasars, we compile a rest-frame UV to IR library of 41,000 optically selected type 1 quasars with Lbol > 1045.7 erg s−1. After fitting the broadband spectral energy distributions (SEDs) with accretion disk and dust components, we find 0.6% of our sample to be hot dust-poor, with rest-frame 2.3 μm to 0.51 μm flux density ratios of −0.5 dex or less. The dust-poor SEDs are blue in the UV–optical and weak in the mid-IR, such that their accretion disks are less obscured and the hot dust emission traces that of warm dust down to the dust-poor regime. At a given bolometric luminosity, dust-poor quasars are lower in black hole mass and higher in Eddington ratio than general luminous quasars, suggesting that they are in a rapidly growing evolutionary state in which the dust-poor phase appears as a short or rare phenomenon. The dust-poor fraction increases with redshift, and possible implications for their evolution are discussed.
