


Vol 62, No 2 (2018)
- Year: 2018
- Articles: 7
- URL: https://journals.rcsi.science/1063-7729/issue/view/12018
Article
3D Doppler Tomography of the X-Ray Binary System Cygnus X-1 from Spectral Observations in 2007 in the HeII λ 4686 Å Line
Abstract
The results of a 3D Doppler tomography analysis for the X-ray binary system Cyg X-1 in the HeII λ 4686 Å line are presented. Information about the motions of gaseous flows outside the orbital plane has been obtained for the first time. Line profiles obtained in June 2007 on the 2-m telescope of the Terskol Branch of the Institute of Astronomy (Russia) and on the 2.1-m telescope of the National Astronomical Observatory of Mexico were used. A detailed analysis of these spectral data is presented: the distribution of the data in time, distribution of orbital phases for the projections, comparison of the line profile shapes for the data from two observatories. The geometry of the total transfer function obtained in the reconstruction is considered. The possibility of applying the profiles obtained to realize 3D tomography is justified. The resolution of the constructed 3D tomogram in velocity space is 60 × 60 × 40 km/s for Vx, Vy, Vz. Fifteen cross sections for 15 different Vz values perpendicular to the orbital plane are presented. The intensity distributions corresponding to the velocities of gaseous structures in the binary system are obtained. The reconstruction was realized using the radio-astronomical approach, developed for solving problems in tomography with a limited number of projections.



Bifurcation near Boundaries of Regions of Stability of Libration Points in the Three-Body Problem
Abstract
The construction of regions of stability in a linear approximation for the triangular libration points in the planar, elliptical, restricted three-body problem is considered, together with the main scenarios for bifurcation when the parameters of the system pass through a boundary of such a region. A new scheme for constructing the boundaries of regions of stability is proposed, which leads to approximate formulas describing these boundaries. The resonance properties of the boundary points (from the point of view of the theory of local bifurcations) are studied. It is shown that one of the main scenarios for bifurcation is the appearance of non-stationary, 4π-periodic solutions close to a triangular libration point.



Spectropolarimetric Observations of Magnetic White Dwarfs with the SAO 6-m Telescope
Abstract
The results of spectropolarimetric observations of a number of magnetic white dwarfs obtained on the 6-m optical telescope of the Special Astrophysical Observatory are presented. The observations were carried out using the SCORPIO focal aperture-ratio reducer in a spectropolarimetric regime. Two characteristic dependences of the degree of polarization on the wavelength are observed. For one group of objects, the degree of linear polarization grows with wavelength, suggesting that the alignment of atoms and molecules in Rydberg states in the atmosphere of the white dwarf due to the action of its magnetic field influences scattering processes. The second group of objects displays an increase in the degrees of both linear and circular polarization with wavelength, providing evidence for the presence of protoplanetary disks around these magnetic white dwarfs, in which the alignment of circumstellar grains leads to the observed behavior.



Evolution and Spectrum of the Radio Emission of Tycho’s Supernova Remnant
Abstract
The radio spectrum of Tycho’s Supernova Remnant is constructed at frequencies 12.6–143 000 MHz for epoch 2010.3, taking into account the secular decrease in the radio flux density of the remnant at the rate d = −(0.46 ± 0.03)%/year:



Distance to the Pulsar B1642–03 and the Influence of the H II Region S27 on Its Dispersion Measure and Scattering Parameters
Abstract
Based on data on the dispersion measure and the interstellar-scattering parameters of the pulsar B1642–03, which is observed in the direction of the emission nebula S27 around the early-type star ζ Oph, it is concluded that this nebula makes a relatively small contribution to its dispersion measure (∼9−23%) and scattering angle (∼9−16%). It is shown that the distance to B1642–03 is 2.2–2.6 kpc.



Geometrical and Kinematic Parameters of the Jet of the Blazar S5 0716+71 in a Helical-Jet Model
Abstract
Periodic variations of the position angle of the inner jet of the blazar S5 0716+71 suggest a helical structure for the jet. The geometrical parameters of a model helical jet are determined. It is shown that, when the trajectories of the jet components are non-ballistic, the angle between their velocity vectors and the line of sight lies in a broader interval than is the case for ballistic motions of the components, in agreement with available estimates. The contradictory results for the apparent speeds of components in the inner and outer jet at epochs 2004 and 2008–2010 can be explained in such a model. The ratio of the apparent speeds in the inner and outer jet are used to derive a lower limit for the physical speed of the components (β > 0.999) and to determine the pitch angle of the helical jet (p = 5.5°). The derived parameters can give rise to the conditions required to observe high speeds (right to 37c) for individual jet components.



Variations of the Blazar AO 0235+164 in 2006–2015
Abstract
The results of optical, radio, and gamma-ray observations of the blazar AO 0235+16 are presented, including photometric (BV RIJHK) and polarimetric (R)monitoring carried out at St. Petersburg State University and the Central (Pulkovo) Astronomical Observatory in 2007–2015, 43 GHz Very Long Baseline Interferometry radio observations processed at Boston University, and a gamma-ray light curve based on observationswith the Fermi space observatory are presented. Two strong outbursts were detected. The relative spectral energy distributions of the variable components responsible for the outbursts are determined; these follow power laws, but with different spectral indices. The degree of polarization was high in both outbursts; only an average relationship between the brightness and polarization can be found. There was no time lag between the variations in the optical and gamma-ray, suggesting that the sources of the radiation in the optical and gamma-ray are located in the same region of the jet.


