TY - JOUR
T1 - Hot-dust-poor Quasars in Mid-infrared and Optically Selected Samples
AU - Hao, Heng
AU - Elvis, Martin
AU - Civano, Francesca
AU - Lawrence, Andy
PY - 2011/6/1
Y1 - 2011/6/1
N2 - We show that the hot-dust-poor (HDP) quasars, originally found in the
X-ray-selected XMM-COSMOS type 1 active galactic nucleus (AGN) sample,
are just as common in two samples selected at optical/infrared
wavelengths: the Richards et al. Spitzer/SDSS sample (8.7% ±
2.2%) and the Palomar-Green-quasar-dominated sample of Elvis et al.
(9.5% ± 5.0%). The properties of the HDP quasars in these two
samples are consistent with the XMM-COSMOS sample, except that, at the
99% (~ 2.5σ) significance, a larger proportion of the HDP quasars
in the Spitzer/SDSS sample have weak host galaxy contributions, probably
due to the selection criteria used. Either the host dust is destroyed
(dynamically or by radiation) or is offset from the central black hole
due to recoiling. Alternatively, the universality of HDP quasars in
samples with different selection methods and the continuous distribution
of dust covering factor in type 1 AGNs suggest that the range of
spectral energy distributions could be related to the range of tilts in
warped fueling disks, as in the model of Lawrence & Elvis, with HDP
quasars having relatively small warps.
AB - We show that the hot-dust-poor (HDP) quasars, originally found in the
X-ray-selected XMM-COSMOS type 1 active galactic nucleus (AGN) sample,
are just as common in two samples selected at optical/infrared
wavelengths: the Richards et al. Spitzer/SDSS sample (8.7% ±
2.2%) and the Palomar-Green-quasar-dominated sample of Elvis et al.
(9.5% ± 5.0%). The properties of the HDP quasars in these two
samples are consistent with the XMM-COSMOS sample, except that, at the
99% (~ 2.5σ) significance, a larger proportion of the HDP quasars
in the Spitzer/SDSS sample have weak host galaxy contributions, probably
due to the selection criteria used. Either the host dust is destroyed
(dynamically or by radiation) or is offset from the central black hole
due to recoiling. Alternatively, the universality of HDP quasars in
samples with different selection methods and the continuous distribution
of dust covering factor in type 1 AGNs suggest that the range of
spectral energy distributions could be related to the range of tilts in
warped fueling disks, as in the model of Lawrence & Elvis, with HDP
quasars having relatively small warps.
KW - quasars: general
KW - surveys
KW - galaxies: evolution
UR - http://www.scopus.com/inward/record.url?scp=79956365528&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/733/2/108
DO - 10.1088/0004-637X/733/2/108
M3 - Article
VL - 733
SP - -
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 108
ER -