V. M. Lyuty

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A 13 Year Study of Spectral Variability in NGC 5548

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad Hemission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 Hmeasurements. The Hvariations follow the continuum variations closely, with a typical time delay of about 20 days. However, a year-by-year analysis shows that the magnitude of emission-line time delay is correlated with the mean continuum flux. We argue that the data are consistent with the simple model prediction between the size of the broad-line region and the ionizing luminosity, r / L 1=2 ion . Moreover, the apparently linear nature of the correlation between the Hresponse time and the nonstellar optical continuum Fopt arises as a consequence of the changing shape of the continuum as it varies, specifically Fopt / F 0:56 UV . Subject headings: galaxies: active — galaxies: individual (NGC 5548) — galaxies: nuclei — galaxies: Seyfert

Intermediate resolution Hβ spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk

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 H emission and the continuum flux varied by a factor of 3. Two large amplitude outbursts, of dierent duration, in continuum and H light were observed i.e.: in October 1994 a brighter flare that lasted1000 days and in July 1997 another one that lasted700 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 of100 days and35 days is present in our data. The flux in the H wings and line core vary simultaneously, a behavior indicative of predominantly circular motions in the BLR. Important changes of the H emission proles were detected: at times, we found proles with prominent asymmetric wings, like those normaly seen in Sy1s, while at other times, we observe proles with weak, almost symmetrical wings, similar to those of Sy1.8s. We further dismiss the hypothesis that the double peaked H proles in this object originate in a massive binary BH. Instead, we found that the radial velocity dierence between the red and blue bumps is anticorrelated with the light curves of H 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 dierence increases, corresponding to smaller radii, as the continuum flux decreases. When the continuum flux increases the hump velocity dierence decreases. These transient phenomena are expected to result from the variable accretion rate close to the central source. The optical continuum and the H 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 2000). Theoretical H proles were computed for an accretion disk, the observed proles are best reproduced by an inclined disk (25) whose region of maximum emission is located roughly at 200 Rg .T he mass of the black hole in 3C 390.3, estimated from the reverberation analysis is Mrev 2:1 10 9 M, 5 times larger than previous

Phase changes of the Be/X-ray binary X Persei

We present high resolution optical spectroscopy and V band photometry obtained during the period 1987{2001 for the Be star X Persei/HD 24534, the counterpart to the X-ray pulsar 4U 0352+30. We nd that throughout this interval X Per is highly active, with signicant photometric and spectroscopic variability. We identify one episode of complete disc loss during this period (1988 May{1989 June), characterised by signicant V =0 :6 mag optical fading and the presence of purely photospheric H and He i 6678 A lines. Two further episodes of pronounced optical fading which did not result in the complete dispersal of the circumstellar disc were also identied (1994 October{1995 October and 1999 November-present). The emission line proles of both H and He i 6678 A also show signicant variability. Cyclic changes in the strength of the peaks in both emission lines are observed, with periods ranging from 0.6{2 yrs { we attribute these to the presence of a one armed density wave in the inner circumstellar disc. Additional structure at large projected velocities is also present in the He i line { suggesting the presence of a signicant density enhancement in the disc near the stellar surface (the double disc of Tarasov & Roche). The evolution of the outer edge of the H emitting region of the circumstellar disc is followed during disc formation, and is found to increase rather slowly. This observation, combined with the presence of the one armed density wave and the rate of disc formation and loss all provide strong evidence for the hypothesis that the circumstellar disc of X Per is a viscous decretion disc, with angular momentum being supplied by an as yet unknown physical mechanism near the stellar surface.

Variability of the H

High-resolution Hα monitoring of Cyg X-1, HD 226868 was carried out during 1996-2002 and the resultant spectra analysed in conjunction with 1.5-12 keV X-ray monitoring. We demonstrate that the Hα line-profiles have complex variability on different timescales, controlled in particular by the orbital period and the focused wind model of mass loss. We find that long-term variability of the mass loss by the supergiant and short-term variability due to clumpy structure of the stellar wind dominate during the low/hard X-ray state and that X-ray photoionization has a relatively small influence on the line-profile shape and EW variability. During the high/soft X-ray state and flaring the effect of photoionization the line-profile and EW of Hα increases but is still unable to describe the loose anti-correlation between EW and the low energy X-ray emission. We propose that variability of the mass loss by the supergiant can change wind velocities in the Stromgren zone around the accretion disc of the secondary, leading to an increase in accretion rate through the disc.

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We present our broadband UBVRI observations of the nucleus of the Seyfert galaxy NGC 4151 from 1989 until 2000 at three astronomical observatories: the Crimean Station of the Sternberg Astronomical Institute, the Special Astrophysical Observatory in the Caucasus, and the Maidanak Observatory of the Ulugbek Astronomical Institute in Uzbekistan. All data have been reduced to a single system and are given for an A=27.″5 aperture. Regular R and I observations show that the pattern of optical variability is the same in all bands; the relative variability amplitude decreases from U to V, but it is even slightly larger in R than in V. The variability amplitude of the component fluctuating on time scales of several months is proportional to the UBV flux from the component varying on times scales of several years. The correlation between the slow and rapid components significantly weakens in the red, and no correlation has been found between the flux from the slow component and the amplitude of the rapid component in R. The color characteristics correspond to the recombination radiation from an optically thick plasma beyond the Balmer limit.

emission of Cygnus X-1 and its connection with the soft X-ray radiation

AbstractWe present our UBV RI observations of the nucleus of the Seyfert Galaxy NGC 5548 from 1990 until 2000 at four astronomical observatories: the Crimean Station of the Sternberg Astronomical Institute, the Special Astrophysical Observatory of the Russian Academy of Sciences, the Crimean Astrophysical Observatory (Ukraine), and the Mount Maidanak Observatory of the Ulugbek Astronomical Institute (Uzbekistan). All data have been reduced to a single system and are given for an A=14.3″ aperture. Large light variations have been observed in the galactic nucleus over the last ten years: the total variability amplitude through the A=14.3″ aperture was n

Nuclear activity of NGC 5548 from UBVRI observations during 1990–2000

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Spectral and photometric monitoring of Seyfert galaxies and quasars in 1998. 1. observations

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