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We present the results of X-ray spectral analysis of the Seyfert type 2 galaxy Mrk 417 ( ɀ ≈ 0.0327 ) based on data from the NuSTAR (3-60 keV) and Swift/BAT (14-150 keV) space observatories. The spectrum from the NuSTAR observatory is well described by a basic power-law model with neutral absorption and an additional reflection component from a cold neutral medium (power-law index $$ \Gamma ={1.63}_{-0.11}^{+0.10} $$ , absorption $$ {\mathrm{N}}_{\mathrm{H}}={3.22}_{-0.39}^{+0.41}\cdot {10}^{23}{cm}^{-2} $$ ). A narrow Fe Kα emission line with an equivalent width $$ {\mathrm{EW}}_{{\mathrm{FeK}}_{\upalpha}}={115}_{-1}^{+2}e\mathrm{V} $$ is present and indicates a moderate density of the medium in which this line is formed. The NuSTAR data together with the Swift/BAT data were analyzed using the more complicated physical models MYTorus and BNTorus. In the first case a power-law index $$ {\Gamma}_{\mathrm{MYTorus}}={1.68}_{-0.09}^{+0.09} $$ and an absorption along the line of sight of $$ {\mathrm{N}}_{\mathrm{HI}.\mathrm{o}.\mathrm{s}}={3.36}_{-0.07}^{+0.04}\cdot {10}^{23}{cm}^{-2} $$ were obtained. The BNTorus model yields a power-law index of $$ {\Gamma}_{\mathrm{BNTorus}}={1.75}_{-0.09}^{+0.09} $$ and an absorption along the line of sight of $$ {\mathrm{N}}_{\mathrm{HI}.\mathrm{o}.\mathrm{s}}={3.72}_{-0.39}^{+0.49}\cdot {10}^{23}{cm}^{-2} $$ . These results provide an estimate of the covering factor for the gas-dust torus of fc ≈ 0.29 − 0.34 and derive absorption-corrected X-ray luminosity of Lintr2 ‐ 10keV ∼ 3.16 ⋅ 1043erg/s. Additional analysis of the observational data in the near IR indicates that the covering factor may even be smaller, at fc ∼ 0.12. These results indicate that the gas-dust torus is most likely compressed along the vertical and has preferably a ring-like geometry.

A search for Hα objects in four fields with an overall area of about 0.14 square degrees in the region of NGC 6910 (the core of the known Cyg OB9 association) has led to the discovery of 64 emission stars, of which 49 are newly detected. The high surface density is indicative of a very rich T association or, possibly, of the projection of several T associations onto one another in this direction. The latter possibility is also indicated by the range of the R photometric stellar magnitudes of the emission stars, 9m. 68-19m. 42. A comparison with earlier observations shows that for many of the stars, the emission line intensity is variable. A P Cyg Hα line profile is recorded for the star V 1515 Cyg with an emission component equivalent width that greatly exceeds the equivalent absorption width. © 2011 Springer Science+Business Media, Inc.

This is a study of the population of B and Be stars in the young, relatively poor, diffuse stellar clusters NGC 6871 and NGC 6913. High resolution spectra are used to study the Hα line of eleven stars in order to detect emission. Emission profiles were found for three stars in the cluster NGC 6871; one of these is a known WR-star and the Be-star BD +35°3956 demonstrates the transition from the B to the Be phase. Spectra of seven of the B stars revealed no traces of emission in the Hα line. During the time of our observations, the Be star V1322 Cyg in the cluster NGC 6913 had a strong emission Hα line profile with substantial variability in intensity and equivalent width. Moderate resolution spectra of seven stars in the cluster NGC 6871 over wavelengths of 4420-4960 A and ten stars in the cluster NGC 6913 over wavelengths of 4050-5100 A are used to classify the series of B and Be stars spectrally and to estimate their T eff and log g. It was found that three of the stars are not members of the clusters NGC 6871 or NGC 6913.

The dependence of the equivalent widths of the 2786–2810 A spectral band and the MgII 4481 A line on the basic parameters (Teff, logg and [M/H]) for 137 bright A-stars shows that 60 of them are candidate peculiar stars. Given the similar behavior of W(2800) and W(4481), it can be assumed that 34 of the stars are chemically peculiar stars. The anomalous values of W(2800), W(4481), and [M/H] vary over wide limits for the rest of the stars, possibly because they are binary.

A number of empirical relationships are shown to indicate an increase in the abundance of phosphorus loge(P) with height in the atmosphere of HR 1512. These include: (a) a correlation of loge(P) with the observed equivalent width Wobs of PII lines; (b) a correlation of loge(P) with the wavelength of the lines; (c) a systematic divergence in the values of loge(P) for lines with different excitation potentials El; in particular, lines with lower El correspond on the average to higher abundances loge(P); and, (d) a distinct dependence of loge(P) on the average geometrical height of formation, Hf. In addition, assuming that loge(P) is constant in the star's atmosphere leads to a systematic discrepancy between the theoretical equivalent widths Wth and the observed values Wobs. By a trial and error method we have found a distribution of the phosphorus abundance loge(P) with height H such that the systematic difference between Wth and Wobs vanishes. It turned out, however, that a simpler, step distribution of loge(P) yields equally good agreement between Wth and Wobs. Although the solution is nonunique, both distributions have some features in common, specifically: (1) a sharp rise in loge(P) occurs in the same range of heights H corresponding to optical thicknesses τ5000 ≈ 10−2–10−3, i.e., stratification of phosphorus takes place in rather high layers of the atmosphere of HR 1512, and (2) the upper bound, logeup(P) = 8.9, is the same in both cases, so that in the region of the rise, loge(P) increases by 3.4 dex. A comparison with available data for HgMn, Am, and Ap type stars shows that similar sharp changes in the abundances loge of several elements occur in other CP stars, at the same optical depths or in even higher layers of their atmospheres.

The results of the high-resolution long-term spectral monitoring of the Herbig Ae star HD 31648 in the regions of emission Hα line, Na I D resonance lines and OI 7774 lines are presented. We confirmed the conclusion, made in previous papers, that the spectral variability of the star in the region of Hα line have a cyclic character. It is manifested itself as the changing of the equivalent width and intensity of Hα line of the time scale of about 1200d. It is shown, that the stellar wind is non-homogeneous and consists of several components, which are differed each other by their velocities. They are observed as in the H line as in Na I D resonance lines. The component’s parameters are changed during the cycle of stellar activity (in the maximum of activity the velocity and density of the wind are taken the largest values and then they are gradually decreased). The investigation of rapid variability of the He I 5876 line on the time scale of a few hours allows find the correlation between the variability of the blue and the red wings of the line. It points at the connection between the accretion and the outflows. Such connection, in particularly, is predicted by the modeling of the wind from young stars made in the frame of the magneto-centrifugal model, the accordance of which for the HD 31648 was shown in the previous papers. In the present work we confirmed this conclusion on the basis of the new data. We found the weak variability of the stellar brightness (about 0.2m), which is agree with the spectral variability (the brightness of the star becomes lower in the maximum of the activity). These changes are well explained by the process of the dust transfer from CS disk by the stellar wind. This process is likely to be more effective in the maximum of activity. An analysis of the variability of other spectral lines shows the agreement between the changing of the Hα line, the Na I D resonance doublet lines and KI 7698 line. The weak connection between the He I 5876 and the Na I D lines is also found. Since the formation regions of He I 5876 and Na I D lines are essentially different, we can conclude that the phenomena, responsible for the observed cyclic variability, take place in a spacious region of the CS envelope. We believe that the most plausible reason of found cyclic variability is the reconstruction of the inner structure of the CS gas envelope, caused by the presence around the star a low mass companion or planet.

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 Hα, and Hβ lines and the equivalent widths (EWλ) 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 Hβ 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.

High resolution spectra with a high signal/noise ratio have been obtained in the region of the HeI D line for 13 dwarfs of spectral types A5 through K0. The variability in the equivalent width of this spectrum line was studied for five of these stars over a period of several hundred days. Significant variability was observed for only one of these stars, θ Cyg.

Spectral and photoelectric (ubvy, Hα, Hβ) observations of the Herbig Ae/Be star HD 259431 are reported. It is found that as its brightness fades, this star becomes bluer in the Paschen continuum and the intensity and equivalent width of the hydrogen emission lines increase. The spectral observations reveal significant variations in the intensity of the Mg II 4481 A photospheric absorption line. A rise and fall in the luminosity by 0m.04 within a period of 5-7 minutes was recorded. Radical variations in the Hα lineshape ("double" → "P Cyg") and flare activity are not only observed in this star, but also in a number of HAEBE stars. It is suggested that flare activity may initiate a change in the velocity gradient at the base of the wind and, thereby, induce "double → P Cyg" or "P Cyg → single" transitions. The nonradial pulsations of this star are also discussed.

The results of high-resolution long-term spectral monitoring of Herbig Ae star HD 179218 in the region of emission Hα line and the sodium resonance doublet Na I D are presented. The received data show the existence of short-term variability (about 10 days) and long-term wave-like variability of equivalent width EW, intensity of circumstellar (CS) emission I and parameters of Hα emission profile. The analysis of these data allows us to suppose the existence of the global variability of parameters of accretion disk.

Quasi-simultaneous photoelectric and spectroscopic observations have been made of the active spotted star VY Ari, showing an increase in the equivalent width of pure emission in the Hα line with a decrease in the star's brightness. Such an increase indicates a relationship between active regions in the chromosphere and the cool photospheric spots. The photometric variability of VY Ari can be described entirely in terms of a zonal model. The spotted regions occupy up to 41% of the star's total surface, with the temperature difference between the quiet photosphere and a spot of 1300 K. The spots lie at middle and low latitudes.

Quasi-simultaneous photoelectric and spectroscopic observations of the active spotted star V 775 Her have been made for the first time and showed an increase in the equivalent width of the pure emission in the Ha line with a decrease in the star’s brightness. Such an increase was due to an increase in electron density in the active regions and demonstrates a connection between active regions and cool spots. The system’s photometric variability is fully described within the framework of a zonal model. The spotted regions occupy up to 42% of the star’s total surface if the temperature difference between the quiet photosphere and a spot is about 900 K. The ratio of the masses of the components of V 775 Her is estimated for the first time.

The results of a spectroscopic and morphological investigation of galaxies with a UV excess Nos. 27, 28, 93, 101, 109, 164, 204, and 217 from the lists of [M. A. Kazarian, 15, 5, 193 (1979)] are given. The equivalent widths, relative intensities, and half- widths of lines are determined. The masses of galaxies Nos. 28, 93, 101, 164, 204, and 217 are also determined.

We discuss the results of simultaneous photoelectric and spectral observations of the flare star EV Lac. The observations of EV Lac were carried out at the National Astronomical Observatory of the Bulgarian Academy of Sciences in August 1986. The photoelectric observations were conducted in the U-color with 1 sec time integration on a 60cm telescope. The effective time of photoelectric observations was 13 hours. The spectral observations were carried out on a two-meter telescope. During one night 35 spectrograms of the star EV Lac were obtained, each of which lasted 2 minutes. The equivalent widths of the Hα emission line were measured. During the photoelectric observations 6 flares were recorded. One of the two comparison stars, C2 showed variable brightness.

The microturbulence in the atmospheres of four F supergiants, ~ Cyg, UMi, p Cas, and ~ Car, is investigated using Fe I lines and on the basis of modern values of the oscillator strengths. It is shown that there exists a strong dependence of the microturbulence velocity ~t on the observed equivalent width. It follows unambiguously from this dependence that the value of St cannot be constant in the atmosphere; instead, it rapidly increases toward the outer layers. The distributions of St(~) in the atmospheres of the investigated stars are determined more accurately. The existence of supersonic values of St in the upper layers of p Cas is confirmed, while for the three other supergiants the values do not exceed the speed of sound. There is a qualitative agreement between the obtained distributions gt(T) and the predictions of the theory of acoustic waves. It is noted that the supersonic values of ~t(~) in the atmosphere of p Cas may be due to the flow of matter observed from this massive supergiant.

1. During the period 1978–1981, the decrease in the light of V 1057 Cyg continued, moreover somewhat more rapidly in 1979–1981 than in 1976–1979. 2. In the bands B and V the decrease in the light has a wavelike nature with an amplitude of about 0m.05 and a characteristic time of more than 200 days. 3. In U and in the line Hα irregular variability with a characteristic time of the order of a day is observed. 4. The equivalent width of the line Hα increased in parallel with the decrease in the continuum. 5. On October 7, 1978 a flare was observed in the line Hα.