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Sergeev S.G.,Crimean Astrophysical Observatory | Sergeev S.G.,Isaak Newton Institute of Chile | Klimanov S.A.,Crimean Astrophysical Observatory | Klimanov S.A.,Isaak Newton Institute of Chile | And 8 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2011

We present further results of the optical observations of the 3C 390.3 nucleus undertaken at the Crimean Astrophysical Observatory since 1992. From the new data obtained in 2000-2007, we find differences in the responses of the Balmer emission lines to the optical continuum variations. Moreover, these responses (i.e. the relationship between line and continuum fluxes) show long-term changes that can be presumably attributed to the evolution of the relationship between the fluxes of the optical and driving continua.We suspect that some small discrepancy between our spectral and photometric measurements of 3C 390.3 can be attributed to the longterm variability of the [OIII] λ 5007Å forbidden line. The cross-correlation analysis of the light curves let us to improve the values of the time delays between continuum and emission-line variations: τcent = 94 ± 6 and 174 ± 16 d for the Hβ and Hα lines, respectively. The black hole mass, derived from the Hβ line, was found to be 2.0 × 109M⊙. This result suggests an even larger black hole mass for the 3C 390.3 nucleus and, therefore, a lower accretion rate under a given luminosity than was previously thought and thus it provides more evidence for anticorrelation between broad-line widths and Eddington luminosity ratios Lbol/LEdd in AGNs. © 2010 The Authors. Journal compilation © 2010 RAS.

Glazunova L.V.,Odessa I I Mechnikov National University | Glazunova L.V.,Odessa National Academy of Telecommunications | Mishenina T.V.,Odessa I I Mechnikov National University | Mishenina T.V.,Isaak Newton Institute of Chile | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014

The absolute parameters and chemical composition of the BY Dra-type spectroscopic binary OU Gem (HD 45088) were determined on the basis of 10 high-resolution spectra. A new orbital solution of the binary system was determined, the binary ephemerides were specified, and the main physical and atmospheric parameters of the binary components were obtained. The chemical composition of both components was estimated for the first time for the stars of such type. © 2014 The Authors.

Doroshenko V.T.,Crimean Astrophysical Observatory | Doroshenko V.T.,Moscow State University | Sergeev S.G.,Crimean Astrophysical Observatory | Sergeev S.G.,Isaak Newton Institute of Chile | And 4 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2012

We present the results of optical spectral and photometric observations of the nucleus of Markarian 6 made with the 2.6-m Shajn telescope at the Crimean Astrophysical Observatory. The continuum and emission Balmer-line intensities varied by more than a factor of two during 1992-2008. The lag between the continuum and Hβ emission-line flux variations is 21.1 ± 1.9days. For the Hα line the lag is about 27days, but its uncertainty is much larger. We use Monte Carlo simulations of random time series to check the effect of our data sampling on the lag uncertainties and we compare our simulation results with those obtained by the random subset selection (RSS) method of Peterson et al. The lags in the high-velocity wings are shorter than those in the line core in accordance with virial motion. However, the lag is slightly larger in the blue wing than in the red wing. This is a signature of infall gas motion. Probably the broad-line region kinematic in the Mrk 6 nucleus is a combination of Keplerian and infall motions. The velocity-delay dependence is similar for individual observational seasons. Measurements of the Hβ line width in combination with the reverberation lag permit us to determine the black hole mass, M BH = (1.8 ± 0.2) × 10 8M ⊙. This result is consistent with active galactic nucleus scaling relationships between the broad-line region radius and the optical continuum luminosity (R BLR ∝ L 0.5) as well as with the black hole mass-luminosity relationship (M BH-L) under an Eddington luminosity ratio for Mrk 6 of L bol/L Edd ∼ 0.01. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

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