Data on the spectral variability of Kaz 102

Results from a spectral study of the quasar Kaz 102 are presented. It is shown that its spectrum varies as a whole; that is, the parameters of both the lines and the continuum change. Based on a comparison of results presented previously and in this paper, it is concluded that over a time of approximately 27.5 years the equivalent widths and relative intensities of the lines have increased, while their half widths have decreased. The spectral composition of Kaz 102 has also changed: new lines, HeII λ4686, [OIII] λ4363, and others, appear in spectra of 2000 and 2001 which were not observed in spectra taken in 1973. The electron density, and the mass and effective radius of the gas component are determined to be 2·107 cm-3, 2·10⁴ M_⊙, and 0.2 pc. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 161–170 (May 2007).     

New Spectrophotometric Data on the Nuclei of the Galaxies Kaz 26 and Kaz 73

The results of a spectroscopic study of the nuclei of the galaxies Kaz 26 and Kaz 73 are presented. The relative intensities of emission lines and the equivalent widths, halfwidths, and expansion velocities of lines at the continuum level are calculated. The electron densities and the masses of the gaseous components of their nuclei are determined. The numbers of stars generating the emission from the gaseous components and nuclei of the galaxies are also determined. The degree of ionization of the gas in each galactic nucleus is calculated. It is concluded that the nucleus of Kaz 26 resembles that of a "starburst" galaxy in its physical properties. It is shown that Kaz 73 is a liner (Sy 3).     

Morphological and spectral study of the galaxies Kaz 69 and Kaz 460

Morphological and spectral studies of the galaxies Kaz 69 and Kaz 460 are reported. The observations were made on the 2.6-m telescope at the Byurakan Observatory using the VAGR multiaperture spectrograph. Isophotes of monochromatic images of the Hα, [NII] λ6584, and [SII] λ6717 lines are constructed. Densifications I and II are found to rotate with north-south oriented axes of rotation. The two densifications (“knots”) have all the kinematic and spectral properties of individual galaxies. It is assumed that Kaz 139 and the densifications I and II were ejected from the nucleus of Kaz 460 at different times, with Kaz 139 probably having been ejected first, although they may all have been ejected simultaneously with different velocities. Along with Kaz 460, these objects form a physical group of galaxies and, at the same time, are a consequence of the activity of the nucleus of Kaz 460. __________ Translated from Astrofizika, Vol. 50, No. 3, pp. 415–426 (August 2007).     

The morphological and spectral investigation of the galaxies Kaz 5, Kaz 92, and Kaz 390

The results of morphological and spectral study of the galaxies Kaz 5, Kaz 92, and Kaz 390 are presented. The observations were made on the 2.6-m telescope at the Byurakan Observatory with the VAGR microlenses spectrograph. Isophotes of the images of the galaxies are constructed in the Hα, [NII] λλ6584 , 6548, and [SII] λλ6731, 6717 emission lines and in the continuum. The masses of Kaz 5 and Kaz 92 are determined to be 8.6 × 10⁸ M_⊙ and 6.1 × 10⁹ M_⊙ , respectively. The mass of the gaseous component in the centers of regions I and IV of Kaz 390, which encompass a 1 pixel area, are also determined. The morphological structure of the central region of Kaz 5 in the observed spectral range, λλ6400–6800?, differs completely from the structure of the same part of the galaxy observed with the 6-m and 2.5-m telescopes. It is shown that these differences in the structure in images of Kaz 5 are mostly explained by the comparatively low resolution of the telescope in combination with the VAGR spectrograph. Absorbing matter also contributes to this effect. It is also shown that a “deficit” of nitrogen has been observed in the region of Kaz 390 studied here (a circle of diameter 40″). Translated from Astrofizika, Vol. 52, No. 1, pp. 63–74 (February 2009).     

Spectral observation of the galaxy Kaz 17

The results of a spectral study of the galaxy Kaz 17 are presented. 150 lines are identified in its spectrum, of which 21 are in emission while the rest are absorption lines. These lines belong to the following elements and ions:..... and FeI. Roughly 56% of the absorption lines belong to FeI. Of the absorption lines, 10 belonging to TiI and FeI are isolated. Because of the closeness of their wavelengths, the rest merge and form separate absorption bands. 10 lines, including 8 emission lines, are unidentified in the spectrum of Kaz 17. In all, 160 lines were observed in the spectrum of Kaz 17. In terms of the structure of the emission lines, Kaz 17 can be assigned to type Sy1, and in terms of the absorption lines, it more closely resembles a normal galaxy. __________ Translated from Astrofizika, Vol. 49, No. 4, pp. 541–551 (November 2006).     

Morphological and Spectral Study of the Galaxy Kaz 73

Morphological and spectral studies of the nucleus and immediately surrounding regions of the galaxy Kaz 73 are reported. The observations were made on the 2.6 m telescope at the Byurakan Astrophysical Observatory in combination with the multi-pupil VAGR spectrograph. Isophotes are constructed for monochromatic images in the Hα, [NII]λ 6584, and [SII]λ6731 lines. It is shown that the surface brightness of the nucleus in monochromatic images of these lines increases rapidly from the edge to the center, with an increase of 5^m for the Hα line. The nucleus of Kaz 73 is found to rotate clockwise about its axis, which is perpendicular to the direction of the arms of the galaxy. The extent of the nucleus in the direction of the arms is found to be a consequence of its rotation; that is, the nucleus is flattened in the direction of the poles. Overall, the nucleus of Kaz 73 has all the kinematic features of an entire galaxy. The masses of the nucleus and its gaseous component are determined to be 6.5⋅10⁸ M• and 1.9⋅10⁴ M•, respectively.__________Translated from Astrofizika, Vol. 48, No. 2, pp. 291–301 (May 2005).     

Observation of the [O III] 1 4363 auroral line in the spectrum of kaz 163

The results of spectroscopic observations of the nucleus of the S component of the galaxy Kaz 163, carried out on the 6-m telescope of the Special Astronomical Observatory in 1982, are presented. The equivalent widths, relative intensities, and half-widths of emission lines were determined. The electron temperature, electron density, and mass of the gaseous component of the nucleus were also determined. The half-widths and equivalent widths varied almost twofold over the time of observations from October 31, 1981, to May 28, 1982. During the same time the intensity of the [O III] λ 4363 auroral line increased fairly strongly. Translated from Astrofizika, Vol. 43, No. 2, pp. 183-189, April–June, 2000.     

On the variability of the spectrum of a galaxy of Seyfert type

We give the results of a spectrophotometric study of Galaxy No. 246 in the list [1]. It is shown that the spectrum of the galaxy is variable.Translated fromAstrofizika, Vol. 37, No. 4, 1994.     

On the variability of emission spectrum of the Sy2 galaxy Mark 6

According to Ambartsumyan, one of the forms of galactic activity is the outflow of gaseous material in the form of jets or clouds from the region of the nucleus at velocities up to hundreds or thousands of km/s, which sometimes leads to the breakup of the nucleus and the ejection of large bursts of material from it. Quite a lot is known about the results of these ejections, especially for quasars and active galaxies. They have been detected and studied in detail with regard to changes in their outer appearance. However, the exact time of the ejections is not known, although statistically they occur frequently and irregularly. The detection of changes in the spectra of galaxies is of special interest, but these are much harder to detect over short times. Nevertheless, the probability of detecting the time of an ejection within a short time is nonzero. Additional new emission components of the hydrogen Hα, Hβ, and Hγ lines over a year in the spectrum of the Sy2 galaxy Mark 6 were first discovered by Khachikian and Weedman in 1969. This paper describes the origin and subsequent interesting fate of this new hydrogen formation (cloud).     

Photometric variability and spectrum of the post-AGB candidate IRAS 19200+3457

We present our photoelectric and spectroscopic observations of the early B supergiant with an IR excess IRAS 19200+3457, a poorly known post-AGB candidate. The star has been found to be photometrically variable. We observed rapid irregular brightness variations with amplitudes up to \(\Delta V = 0\mathop .\limits^m 4, \Delta B = 0\mathop .\limits^m 4\), and \(\Delta U = 0\mathop .\limits^m 5\). IRAS 19200+3457 and three other hot post-AGB stars—V886 Her, V1853 Cyg, and LSIV—12°111—exhibit a similar variability pattern. Our low-resolution spectroscopic observations in the period 2001–2003 show that the spectrum of IRAS 19200+3457 represents an early B star with hydrogen emission lines originating from a circumstellar gaseous envelope. The HeI λ5876 Å, λ6678 Å, λ7065 Å, and OI λ7774 Å lines are in absorption. The hydrogen and, probably, HeI lines proved to be variable. Our observations confirm the conclusion that IRAS 19200+3457 belongs to the class of intermediate-mass protoplanetary objects.     

The X-ray spectrum and variability of the Seyfert 2 galaxy NGC 7172

We present evidence of flux variability, on both short (hours) and long (months) time-scales, of the Seyfert 2 galaxy NGC 7172. These results are based on the ASCA observation of NGC 7172 performed in 1996 May. The source was detected at a rather low flux level, about 3 times fainter than its usual state (including 1 yr before, when it was also observed by ASCA ).   The source also varied by about 30 per cent during the observation, confirming the presence of a type 1 nucleus in its centre. However, its spectrum appears to be flatter than the typical Seyfert 1 spectrum (in agreement with findings on other Seyfert 2s), posing problems for the unification model unless complex absorption is invoked.     

Morphology and variability of helium line profiles in the P Cygni spectrum

The morphology and variability of 13 helium lines in the P Cygni optical spectrum have been studied in detail over a period of three years. It is found that most lines in the sample have often shown profiles with a complicated structure: discrete components are superposed on a broader underlying P Cyg profile. Multiple sets of components were frequently observed. The radial velocity of the discrete components varies with time. In this article the velocity evolution of two sets of components is studied in detail and the corresponding velocity laws are derived. It is found that the velocity variations in the helium and hydrogen discrete components are correlated. The recurrence timescale for the appearance of new helium components is estimated.An attempt is made for a qualitative interpretation of the obtained results.     

Night-to-night variability of the emission lines in the spectrum of the Seyfert galaxy NGC 3227 nucleus

This is a study of optical emission lines of the nucleus of the Seyfert galaxy NGC 3227. This work is based on 53 spectrograms obtained with the 6-m telescope at the brightness maximum of this galactic nucleus on January 12–15, 1977. A set of profiles of the hydrogen H_α, and H_β lines and the equivalent widths (EW_λ) of six emission lines and blends averaged over series of observations are presented. Broadening of the hydrogen line profiles was observed over the three days. At a level of 0.50 times the peak brightness the hydrogen line profiles were broadened by 12%, 35%, and 44%, respectively. The broadening of the H_β line was accompanied by a reduction in its equivalent width (EW _; ). It is suggested that a flare was observed in the nucleus of the galaxy on a time scale of 3 days, possibly caused to a shock wave in long-lived flows from the galaxy nucleus. __________ Translated from Astrofizika, Vol. 49, No. 4, pp. 499–510 (November 2006).     

Orbital parameters and variability of the emission spectrum for the massive binary system 103 Tau

Based on high-resolution spectra taken near the He I 6678 Å line for the massive binary system 103 Tau, we have detected a weak absorption component belonging to the binary’s secondary component. We have measured the radial velocities of both components, improved the previously known orbital parameters, and determined the new ones. The binary has an orbital period P _orb = 58.305^d, an orbital eccentricity e = 0.277, a radial velocity semi-amplitude of the bright component K _A = 44.8 km s^?1, and a component mass ratio M _A /M _B = 1.77. The absence of photometric variability and the estimates of physical parameters for the primary component suggest that the binary most likely has a considerable inclination of the orbital plane to the observer, i ≈ 50°?60°. In this case, the secondary component is probably a normal dwarf of spectral type B5–B8. Based on the spectra taken near the H _α line, we have studied the variability of the emission profile. It is shown to be formed in the Roche lobe of the secondary component, but no traces of active mass exchange in the binary have been detected.     

X-ray variability of the Seyfert 1 Markarian 335: power spectrum and time lags

To investigate further the comparison between active galactic nuclei (AGN) and black hole X-ray binaries, we have studied the main X-ray variability properties of the Seyfert 1 galaxy Mrk 335. We put particular emphasis on the X-ray time lags, which is a potentially important diagnostic of physical models. From a 100 ks observation by XMM–Newton , we show that the power spectrum of this source is well fitted by a bending power-law model, and the bend time-scale T _b is precisely at the value predicted by the T _b versus Hβ linewidth relation of McHardy et al. Variations in different energy bands show time-scale-dependent time lags, where higher energy bands lag lower ones. The lag, τ, varies as a function of the Fourier frequency, f , of the variability component in the light curves as  τ∝ f ⁻¹  at low frequencies, but there is a sharp cut-off in the lags at a frequency close to the bend frequency in the power spectrum. Similar behaviour is seen in black hole X-ray binary systems. The length of the time lags increases continuously with energy separation, in an almost loglinear relation. We show that the lag spectra can be produced by fluctuations propagating through the accretion flow as long as the energy spectrum of the X-ray emitting region hardens towards the centre.