The continua of type 1 Seyferts from 0.3 to 100 microns have been examined. We focus on the modifying effects of dust, both in terms of absorption and re-radiation. After allowance is made for dust and the presence of extranuclear contributions to the IRAS fluxes, there remains a ubiquitous underlying distribution which we believe to be non-thermal. There is evidence that the thermal infrared components corresponding to hot and warm dust may be associated with the broad and narrow emission line regions.

We have analyzed far-IR (IRAS) data for a sample of optically selected Seyfert galaxies. The far-infrared emission is uncorrelated, or at best weakly correlated, with the UV-optical emission from these sources. We find the far-IR emission to be extended in a number of objects. We discuss the possibility that Seyfert galaxies are undergoing circumnuclear bursts of star formation. For comparison with the large aperture IRAS data we have also obtained new ground-based measurements at 10 and 20 μm for a sample of 17 Seyfert galaxies. Conclusive evidence for extended 10 and 20 μm emission is seen in 7 out of 17 objects. In addition, almost all of the objects have ground-based fluxes which are smaller than those measured by IRAS. Finally, for five objects the emission appears to be more extended at 10 μm than at 20 μm. This would be expected if the 10 μm emission arose, in part, from a population of very small grains for which single photon heating is important.

NGC 2992 is a nearby Seyfert galaxy (z=0.008, 1″=150 pc, for HO=75 km s−1 Mpc−1) seen almost edge-on (i=70°). A dust lane crossing the galaxy has been detected (Burbidge et al. 1972, see also Fig. 1) and the presence of two extended radio-emitting regions at position angles P.A. 130° and P.A. 160° has been reported (Ulvestad and Wilson, 1984).

Radio-quiet and normal radio-loud quasars have very similar spectral properties in the ultraviolet, optical and near infrared regions, but their radio powers differ by several orders of magnitude. Somewhere between the near infrared and the radio their spectra must diverge dramatically.

The IRAS survey detected 17 radio quiet quasars and luminous Seyfert 1's with −29. 5 ≤ Mv ≤ −21.6 (for Ho = 75). By coadding the survey data and using pointed observations, we have detections of most of these objects in all four IRAS passbands. The spectra are all rising with wavelength all the way to 100μ. We are measuring fluxes in the centimeter, millimeter, and, together with R Cutri, the near infrared and optical regions for each of these objects. Our goal is to constrain the location, shape, and spectral context of the low frequency cutoffs. Here we present the IRAS, millimeter and centimeter data. Measurements at the other wavelengths are still in progress.

Although the spectra are rising steeply between 60μ and 100μ, we find that all of our objects are undetectable at 1.3 mm with the NRAO 12-m telescope. Our limits are typically an order of magnitude below the 100μ fluxes. (Ennis et al (1982) and Robson et al (1985) have already shown that the 1 mm fluxes of some radio quiet quasars must be below the extrapolation of the near infrared continuum.) Our objects are all extremely weak or undetected with the VLA at 2 cm and 1.3 cm, at levels typically three orders of magnitude below the 100μ fluxes. The sharpness of the required cutoffs allows us to rule out the hypothesis that the infrared is synchrotron radiation with the cutoff due to an absence of low energy electrons. The high frequency of the cutoffs makes free-free absorption implausible, but not impossible. It is possible that synchrotron self-absorption is suppressing the radio. There is circumstantial evidence that the far infrared is thermal dust emission. This would require a lower cutoff in the distribution of dust temperatures, which we think we can explain.

The structure of active galaxies is related to the activity of their nuclei. The activity of galaxies is known to be caused by the processes occurring in their central regions with sizes of less than 10 pc, luminosities of 1044 erg/s (exceeding by 3–4 orders of magnitude the typical values for normal galaxies), and masses not exceeding 1% of the total galactic mass.

We present some preliminary results on the determination of the masses of the central bodies of AGN and QSOs. They are given as an example of the statistical studies we are performing, based on a catalogue which we are still improving, and which is to be a compilation of many observational parameters concerning these objects.

The hydrodynamical conception of the spiral structure generation in the galaxies with a “kink” on the rotation curve is discussed. It treats the spirals as density waves in gas component of galactic disks. The main results of the fifteen-year study are presented. References are made to the papers of authors that prove a) the “gas” conception of the Galaxy spiral structure, b) the identity of equations for rotating shallow water and galactic gas disk, c) the method of laboratory modelling of galactic spirals induced by hydrodynamical mechanisms in shallow water experiments with the “Spiral” set up. The linear stability theory describes the mechanism of spiral arm formation and gives the parameters of the arms. Experiments agree with theory. Besides, they show banana-like vortices between the arms near the generator. Observational data on the galaxy NGC 1566 reveal a pronounced velocity kink and may be explained in terms of the spiral-vortex gas conception. The results of laboratory experiments and numerical simulations allow us to suggest certain hypothesis concerning observational evidences of the spiral-vortex structure.

Recent observations of spectral variability in active galactic nuclei have established the connection between the broad emission-line and optical continuum flux changes. The inferred size of the broad-line region is at least an order of magnitude smaller than conventional estimates based on photoionization models, which leads to new conclusions about the nature of the broad-line region.

The emission lines variability in the spectra of Seyfert galaxies nuclei has been known for more than 20 years. The first report on the problem under consideration was made by Bardin et al.(1967). They published the data on the variation of relative intensities of forbidden 4959+5007 A and 4363 A [OIII] lines in the spectrum of NGC 5548 galaxy nucleus that exceed the errors of observations. It was noticed also that NGC 5548 was the second galaxy where the considered lines show variability. At least four review papers have been published: Lyutyi and V. Pronik (1975), Collin-Souffrin(1980), I. Pronik (1980), Penston(1982).

Penfold's UBV observations of the Nuclei of the Seyfert galaxies NGC 1566, NGC 3227, NGC 3783, NGC 6814, NGC 7469, Mk 50 and IC 4329A are examined to look for a possible periodicity in the variation of the magnitudes and colors. A method based on the fitting of sinusoidals and the calculation of the multiple correlation coefficient adequated to the analysis of observations unequally spaced in time is used to analyse the data. Four of the seven galaxies studied show a high probability of having periodic component in the variation. Recent UBV observations were used to test the components in two of them.

The analysis of the available data about spectral observations of nucleus and gas velocity field in NGC 1275 leads to a conclusion on the presence in the nucleus of several spatially separated variable sources responsible for a complex variable emission in Hβ and [OIII] lines profiles.

The spectral observations of NGC 1275 nucleus in the range of 3700-7000 AA being carried out since 1971 to 1978 showed the existance of hydrogen and forbidden emission lines variability with the time scale of 5–6 and 1–2 years (Pronik, 1980). Observations on 6-m telescope during 4 nights in January, 1977 permit to reveal the scale variability of these lines 2–3 days, too (Merkulova, Pronik, 1985). These results evidenced the necessary of close photoelectric series of spectral observations of the galaxy nucleus with the filling factor of several days and hours.

The real and imaginary changes of shapes of emission lines in spectra of two Seyfert galaxies NGC1068 and MRK79 are examined.

The spectra of NGC 5548 galaxy nucleus obtained at the Crimean Aetrophysical observatory on 2.6-m Shain telescope from April till August 1985 showed strong variations of Hβ line profile. The profile being almost symmetrical in April became more and more asymmetrical in June-August, the flux in blue wing increased twofold in respect to the red one. Such variations of line profile were accompanied by continuum decrease.

We suppose, that the observed variations might be explained by the appearance of the absorbing matter located on the line of sight between the nucleus and the gas responsible for the intensity increase in the blue wing of Hβ line. This gas might have been ejected close to the line of sight direction.

Measurements of the 5 GHz flux densities of faint radio sources (S ~ 80 mJy) in a complete sample have been made at three epochs spanning a 15-year timebase. These measurements provide data for a statistical investigation of activity in faint radio sources. Here we report the results for some outstanding objects.

The spectral evolution between 0.3 and 15 GHz of the extragalactic radio sources 0235+164 and 1611+343 (DA406) is presented. The data show two very different forms of behavior. For 0235+164 the variations over the entire frequency range are correlated and consistent with being intrinsic to the source, whereas for DA406 an extrinsic cause for the variability seems probable.

3C 120 (z=0.033) has the optical spectrum typical of a Seyfert I Galaxy, however unlike most Seyfert Galaxies it exhibits strong radio emission with a compact component where VLBI observations indicated superluminal expansion. It could therefore be classified as a mini Radio Loud Quasar.

One of the principal problems of investigation of AGNs is to understand the nature of the central objects and the physical processes which yield their gigantic luminosities. This requires us to consider the innermost parts of AGNs (3–30 gravitational radii, i.e. ≲ 1016 cm: angular size less than 1 milliarcsecond).

1–3d variations of the relative shape of broad emission line profiles of active galactic nuclei (AGN) are perhaps the most informative probe of the innermost parts of AGNs (r = 1015–16 cm from the centre). Optimal objects for these observations are Sy 1.5 with strong variations of the non-thermal continuum (e.g. NGC 4151). The expected amplitude of the variations ranges from a few percent to 10–20%. The optimal spectral resolution is 0.5–5 Å. It is very desirable to complement spectral observations with photometric data. The results of the first set of such observations with the 6-meter telescope are reported.

Gas in the shadow of clouds in the outer parts of the broad line region can radiate a considerable fraction (dozens of percent) of the narrow emission line flux. The variability of the X-ray luminosity of the central source should result in significant variations of the gas emission on a timescale of months. Particularly strong changes of line intensities and column densities of gas in the shadow (~ 1023 cm−2) can be produced by phase transfer between two thermally stable fluids with temperatures 10–20×103 K and 40–100×103 K, which can exist in the shadow of clouds.

In high density gas n(H) ~ 107cm−3 the electron impact and charge transfer OIV+HI→OIII+HII secure high emissivity of gas in [OIII] lines only with low hydrogen and helium ionization, when ne~ n(OIII) ~ 106−107 cm−3. Such condition is possible in HI-zones where oxygen is ionized by soft X-ray (Auger effect). It is shown, that the observed luminosity of NGC 1275 nucleus in 4959+ 5007 Å [OIII] lines can be explained by the electron impact in gas with hydrogen concentration n(H) ~ 1012 cm−3 and does not contradict to a possibility of lines variations within several days.