Issue |
A&A
Volume 492, Number 3, December IV 2008
|
|
---|---|---|
Page(s) | 637 - 650 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20078957 | |
Published online | 06 November 2008 |
Eddington ratios of faint AGN at intermediate redshift: evidence for a population of half-starved black holes*
1
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: igavignaud@aip.de
2
Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstr., 85741 Garching, Germany
3
Integral Science Data Centre, Ch. d'Écogia 16, 1290 Versoix, Switzerland
4
Geneva Observatory, Ch. des Maillettes 51, 1290 Sauverny, France
5
INAF-Osservatorio Astronomico di Bologna, via Ranzani, 1, 40127, Bologna, Italy
6
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
7
Laboratoire d'Astrophysique de Marseille (UMR6110), CNRS-Université de Provence, 38 rue Frederic Joliot-Curie, 13388 Marseille Cedex 13, France
8
Laboratoire d'Astrophysique de Toulouse-Tarbes, Université de Toulouse, CNRS, 14 avenue Édouard Belin, 31400 Toulouse, France
9
IASF-INAF, via Bassini 15, 20133, Milano, Italy
10
IRA-INAF, via Gobetti,101, 40129, Bologna, Italy
11
INAF-Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy
12
INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy
13
Institut d'Astrophysique de Paris, UMR 7095, 98bis Bvd. Arago, 75014 Paris, France
14
School of Physics & Astronomy, University of Nottingham, University Park, Nottingham, NG72RD, UK INAF-Osservatorio Astronomico di Brera, via Brera 28, Milan, Italy
15
Canada France Hawaii Telescope corporation, Mamalahoa Hwy, Kamuela, 96743, USA
16
Observatoire de Paris, LERMA, 61 avenue de l'Observatoire, 75014 Paris, France
17
Università di Bologna, Dipartimento di Astronomia, via Ranzani, 1, 40127, Bologna, Italy
18
Università di Milano-Bicocca, Dipartimento di Fisica, Piazza delle Scienze, 3, 20126 Milano, Italy
Received:
29
October
2007
Accepted:
17
October
2008
We use one of the deepest spectroscopic samples of broad-line active
galactic nuclei (AGN) currently available, extracted from the VIMOS VLT
Deep Survey (VVDS), to compute the and
virial-mass estimates of 120 super-massive black holes in the redshift
range
and
.
We find that the mass-luminosity relation shows considerably
enhanced dispersion towards low AGN luminosities (
).
At these luminosities, there is a substantial fraction of black holes
accreting far below their Eddington limit
(
), in marked contrast to what is
generally found for AGN of higher luminosities. We speculate that these
may be AGN on the decaying branch of their lightcurves, well past
their peak activity. This would agree with recent theoretical
predictions of AGN evolution.
In the electronic Appendix of this paper we publish an update of the VVDS
type-1 AGN sample, including the first and most of the
second-epoch observations. This sample contains 298 objects of
which 168 are new.
Key words: galaxies: active / galaxies: Seyfert / galaxies: nuclei
© ESO, 2008
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