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Äàòà èçìåíåíèÿ: Mon Oct 9 11:14:23 2006
Äàòà èíäåêñèðîâàíèÿ: Tue Oct 2 10:18:21 2012
Êîäèðîâêà:

Ïîèñêîâûå ñëîâà: arp 220
CONTINUUM AND BROAD EMISSION LINE VARIABILITY
OF SEYFERT GALAXIES
V.T. Doroshenko 1,2 , S.G. Sergeev 2 , V.I. Pronik 2
1 Crimean Lab. of the Sternberg Astronomical Institute, Moscow University, Russia
2 Scientific­Research Institute, Crimean Astrophysical Observatory, Ukraine;
p/o Nauchny, 98409, Crimea, Ukraine
vdorosh@sai.crimea.ua
We focused on the observed properties of some Seyfert galaxies without detailed discussion
of underlying physical mechanisms. Our purpose was to show a diversity of observed e#ects
due to variability in spectra of six galaxies (NGC 4151, NGC 5548, Mrk 6, Ark 120, 3C 390.3,
Arp 120B), optical spectral and photometric monitoring of which was carried out in the
Crimean Astrophysical Observatory and Crimean Laboratory of the Sternberg Astronomical
Institute over many years. This monitoring shows that
. All light curves demonstrate a variability on di#erent time scales from days to years.
. Amplitude of variations increases with increasing of the time interval of observations.
. The flux in emission lines changes in response to the flux variation of the ionizing
continuum source with some time delay. Thus, the emission lines ``echo'' or ``rever­
berate'' the continuum changes. This time delay is due to light­travel time e#ects
within the BLR.
. The time delay of the broad H# emission line flux relative to optical continuum in
the vicinity of the H# line lies in an interval from 9.2 days for Arp 102B to 80 days
for 3C 390.3. This means that a region of the most e#ective emission in the H# and
H# lines is fairly small, and it is located at a distance of about 9 -- 80 light days from
the continuum source.
. We found one very strange and inexplicable case (3C 390.3) when a lag calculated
from the broad H# line significantly exceeds that of the H#. In all other cases, the
H# and H# lines have a similar lag.
. We revealed a slightly di#erent lag for two time intervals for NGC 5548: #26 days in
1972--1988 and # 18 days in 1989--2001.
. Analysis of the lag as a function of the radial velocity does not show any reliable
evidence of the pure radial dominated outflow, possibly, except for NGC 4151. A
weak evidence of radial inflow was found in Mrk 6 and Ark 120. Predominantly, we
found that there is no pure radial inflow or outflow in the BLR of the considered
galaxies. In all cases, the kinematics mainly looks like a chaotic or rotational motion.
. We also found that the lag for the central part of the broad H# emission line is slightly
larger than for wings (NGC 5548).
. The lag slightly increases with increasing of the continuum flux (Ark 120). This
fact is consistent with a virial relation between the velocity field and the distance
of the emitting region: the velocity field diminishes with increasing distance from

the central continuum source. This implies that the velocity field is dominated by a
central massive object.
. Not only the flux of broad emission line but also the line profiles appreciably changed
with time. The emission­line profile changes usually occur on a time scale that is
much longer than the light­travel time scale.
. In all cases, the excess between the normalized Balmer profiles and the mean normal­
ized profile shows a very complicated behavior both over time and wavelength, and
it can hardly be related to the expected reverberation signal from the simple disk
model. The profile evolution for some galaxies (NGC 4151, Mrk 6, 3C 390.3) can
be reproduced to larger or smaller extent with the two­component model in which
profile changes are due to changes in the relative strength of two variable compo­
nents with a fixed shape. The double peaked profile was often observed among the
discussed objects. Profile decomposition gives one component that dominates in the
central part of the profile, while the double peaked component dominates in the profile
wings. However, the moving features of the profile shapes observed, e.g., in 3C 390.3,
NGC 4151, and Arp 102B can be a result of rotating redistribution of matter in the
Keplerian disk.
Acknowledgements.The research was made in partly by the award UP 1­2549­CR­03 of
the US Civilian Research and Development Foundation for the Independent States of the
Former Soviet Union (CRDF) and by the Russian Foundation for Basic Research (RFBR)
grant 06­02­16843.