Issue |
A&A
Volume 376, Number 3, September IV 2001
|
|
---|---|---|
Page(s) | 775 - 792 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20011011 | |
Published online | 15 September 2001 |
Intermediate resolution H
spectroscopy and
photometric monitoring of 3C 390.3*,**
I. Further evidence of a nuclear accretion disk
1
Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167, Russia e-mail: ashap@sao.ru
2
Isaac Newton Institute of Chile, SAO Branch
3
Instituto Nacional de Astrofísica, Optica y Electrónica, Apartado Postal 51, CP 72000, Puebla, Pue., México
4
Observatorio Astronómico Nacional, UNAM, Apartado Postal 877, CP 22860, Ensenada B.C., México
5
Sternberg Astronomical Institute, University of Moscow, Universitetskij Prospect 13, Moscow 119899, Russia
6
DAEC, Observatoire de Paris, Section de Meudon, Place Janssen, 92195 Meudon, France
7
Abastumani Astrophysical Observatory, Georgian AS, Mt. Kanobili, 383762, Abastumani, Georgia
Corresponding author: L. Carrasco, carrasco@inaoep.mx
Received:
21
February
2001
Accepted:
13
June
2001
We have monitored the AGN 3C 390.3 between 1995 and 2000.
A historical B-band light curve dating back to 1966 shows a large
increase in brightness during 1970-1971, followed by a gradual decrease
down to a minimum in 1982. During the 1995-2000 lapse the broad Hβ emission
and the continuum flux varied by a factor of ≈3. Two large amplitude
outbursts, of different duration, in continuum and light were
observed i.e.: in October 1994 a brighter flare that lasted ≈1000 days
and in July 1997 another one that lasted ≈700 days
were detected. The response time lag of the emission lines relative to flux changes of the
continuum has been found to vary with time i.e. during 1995-1997 a lag of about 100 days is
evident, while during 1998-1999 a double valued lag of ≈100 days and ≈35 days is present in our data. The flux in the Hβ wings and line core vary simultaneously, a
behavior indicative of predominantly circular motions in the BLR.
Important changes of the Hβ emission profiles were
detected: at times, we found profiles with prominent asymmetric wings, like those normaly
seen in Sy1s, while at other times, we observe profiles with weak, almost symmetrical
wings, similar to those of Sy1.8s. We further dismiss the hypothesis that the double
peaked
profiles in this object originate in a massive binary BH. Instead,
we found that the radial velocity difference between the red and blue bumps is
anticorrelated with the light curves of Hβ and continuum radiation. This implies that
the zone that contributes most of the energy to the emitted line changes in radius
within the disk. The velocity difference increases,
corresponding to smaller radii, as the continuum flux decreases. When
the continuum flux increases the hump velocity difference decreases. These
transient
phenomena are expected to result
from the variable accretion rate close to the central source.
The optical continuum and the
flux variations might be
related to changes in X-ray emission modulated by a variable
accretion rate, changing the surface temperature of the disk,
as a result of a variable X-ray irradiation (Ulrich [CITE]).
Theoretical
profiles were computed for an accretion disk,
the observed profiles are best reproduced by an inclined disk (
)
whose region of maximum emission is located roughly at 200 Rg.
The mass of the black hole in 3C 390.3, estimated from the reverberation analysis is
, 5 times larger than
previous estimates (Wandel et al. [CITE]).
Key words: galaxies: active / galaxies: Seyfert / galaxies: individual: 3C 390.3 / line: profiles
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.