Issue |
A&A
Volume 468, Number 2, June III 2007
The XMM-Newton extended survey of the Taurus molecular cloud
|
|
---|---|---|
Page(s) | 603 - 612 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20077092 | |
Published online | 03 April 2007 |
The HELLAS2XMM survey
X. The bolometric output of luminous obscured quasars: The Spitzer perspective
1
Dipartimento di Astronomia, Università degli Studi di Bologna, via Ranzani 1, 40127 Bologna, Italy
2
INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
3
INAF - Istituto di Radioastronomia (IRA), via Gobetti 101, 40129 Bologna, Italy
4
Max Planck Institut für Extraterrestrische Physik (MPE), Giessenbachstrasse 1, 85748 Garching bei München, Germany
5
INAF - Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio-Catone (RM), Italy
6
Dipartimento di Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
Received:
12
January
2007
Accepted:
21
March
2007
Aims.We aim at estimating the spectral energy distributions (SEDs) and the physical
parameters related to the black holes harbored in eight high X-ray-to-optical ()
obscured quasars at
selected in the 2–10 keV band from the HELLAS2XMM survey.
Methods.We use IRAC and MIPS 24 μm observations, along with optical and Ks-band photometry,
to obtain the SEDs of the sources.
The observed SEDs are modeled using a combination of an elliptical template and torus emission
(using the phenomenological templates of Silva et al. 2004)
for six sources associated with passive galaxies;
for two point-like sources, the empirical SEDs of red quasars are adopted.
The bolometric luminosities and the relation are used to provide an
estimate of the masses and Eddington ratios of the black holes residing in these AGN.
Results.All of our sources are detected in the IRAC and MIPS (at 24 μm) bands.
The SED modeling described above is in good agreement with the observed near- and
mid-infrared data.
The derived bolometric luminosities are in the range 1045-1047 erg s-1, and the
median 2–10 keV bolometric correction is ≈25, consistent with the widely adopted
value derived by Elvis et al. (1994).
For the objects with elliptical-like profiles in the Ks band, we derive high stellar
masses (0.8-6.2)
1011
, black hole masses in the range
(0.2-2.5)
109
, and Eddington ratios
, suggesting a low-accretion phase.
Key words: quasars: general / galaxies: nuclei / galaxies: active
© ESO, 2007
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