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11.
V. L. Afanasiev N. V. Borisov Yu. N. Gnedin T. M. Natsvlishvili M. Yu. Piotrovich S. D. Buliga 《Astronomy Letters》2011,37(5):302-310
We present the results of our spectropolarimetric observations for a number of active galactic nuclei (AGNs) carried out at
the 6-m telescope with the SCORPIO focal reducer. The derived wavelength dependences of the polarization have been analyzed
by taking into account the Faraday rotation of the polarization plane on the photon mean free path in a magnetized accretion
disk. As a result, based on traditional accretion disk models, we have determined the magnetic field strength and distribution
and a number of physical parameters of the accreting plasma in the region where the optical radiation is generated. 相似文献
12.
13.
V. L. Afanas’ev N. V. Borisov Yu. N. Gnedin S. D. Buliga T. M. Natsvlishvili M. Yu. Piotrovich 《Astronomy Reports》2014,58(10):725-732
Spectropolarimetric observations of a number of Active Galactic Nuclei obtained using the SCORPIO-2 aperture focal reducer installed on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences are used to estimate physical parameters of these objects. The measured polarization and its wavelength dependence are consistent with the expectations of a standard accretion-disk model taking into account the effect of Faraday depolarization over the mean free path of the emitted photons. Estimates of the magnetic field in the accretion disk near the innermost stable orbit and the spin of the accreting central black hole are obtained. It is concluded that supermassive black holes with standard accretion disks and equal magnetic and radiative pressures are primarily Kerr black holes. 相似文献
14.
Churyumov K. I. Luk'yanyk I. V. Vlassyuk V. V. Borisov N. V. 《Earth, Moon, and Planets》2002,90(1-4):141-146
We obtained spectra of comet C/1999 S4 (LINEAR) with the UAGS spectrograph(long slit and CCD) installed on the 1-m Zeiss reflector of the SAO of the RAS(Northern Caucuses, Nizhny Arkhyz) on July 23/24, 26/27 and 27/28, 2000. OnJuly 22/23, before the splitting of the cometary nucleus, several emission lines,such as C2, C3, CN, NH, CH, NH2, CO+, H2O+ wereclearly identified in the spectra. The inspections of the CCD spectra obtainedon July 27/28, 2000 reveals only very weak emission lines superimposed on thesolar reflection spectrum. From analyzing the surface brightness profile of C2 along the slit the velocity of separation of two secondary fragments (V = 10 km/h) and the energy of the fragment separation (E = 8.7 × 1015 erg) were estimated. A luminescence cometary continuum of 26% of the total continuum level is detected in the spectra of the comet at 5000 Å. Possible mechanisms of nucleus splitting are discussed. 相似文献
15.
G. Beskin N. Borisov V. Komarova S. Mitronova S. Neizvestny V. Plokhotnichenko M. Popova 《Astrophysics and Space Science》1997,248(1-2):51-57
I summarize fully-sampled observations of the 3 mm emission from CO and HCN in the inner arcminute of NGC 1068. The CO emission
is distributed in the form of a molecular bar, coincident with the infrared bar, from which emanate two spiral arms. A relatively
weak concentration of CO line emission is found at the nucleus. By contrast, the HCN emission is strongly concentrated at
the center, with relatively weak emission in the region of the star-forming arms. The ratio of HCN to CO integrated intensities
is about 0.6 over the central r ≉ 175 pc and is the highest ratio measured in the center of any galaxy; the ratio reflects
the high thermal pressure (TK ~ 50 K, n[H2] ~ 4 × 106 cm-3) in the few hundred parsecs surrounding the nucleus.
The kinematics in the star-forming arms are well described by circular orbits, with ordered noncircular motions of < 30 km
s-1 that may be attributed to spiral density wave streaming. Interior to the bar, noncircular motions dominate the gas kinematics.
A model of the CO kinematics contrains any Inner Lindblad Resonance to be close to the location of the hundred-parsec scale
HCN ‘disk’. At the nucleus, the spatially unresolved CO emission shows a triplet velocity structure characteristic of kinematically
independent regions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
17.
We perform the bifurcation analysis of the Kepler problem on
and
. An analog of the Delaunay variables is introduced. We investigate the motion of a point mass in the field of a Newtonian
center moving along a geodesic on
and
(the restricted two-body problem). For the case of a small curvature, the pericenter shift is computed using the perturbation
theory. We also present the results of numerical analysis based on an analogy with the motion of a rigid body. 相似文献
18.
O. V. Stepanets A. N. Ligaev A. P. Borisov A. V. Travkina V. M. Shkinev T. V. Danilova A. Yu. Miroshnikov V. I. Migunov 《Geochemistry International》2009,47(7):657-671
This paper reports the results of the investigations of 2006–2007 on the distribution and migration forms of artificial radionuclides and chemical elements in the Ob-Irtysh water system. Three regions were studied. One of them is a local segment of the Ob River upstream from the confluence with the Irtysh River; its investigation allowed us to estimate the general radioecological state of the aquatic environment affected by the activity of the Tomsk 7 plant. The second region is a local segment of the Irtysh River upstream from its confluence with the Ob River, where the influence of emissions from the NPO Mayak could be estimated. The third region is the water area of the Ob River after its confluence with the Irtysh River. It characterizes the real level of radioactive and chemical contamination of the middle reaches of the Ob River.In order to explain horizontal variations in the distribution of radionuclides in the upper layer of bottom sediments collected at various sites, the results of sorption-kinetic experiments with radioactive tracers in the precipitate-solution system were used. The investigation of the migration forms of trace elements and radionuclides occurring in river water was based on the method of tangential-flow membrane filtration.Chemical element contents were determined in 400-ml water samples. A set of Millipore polysulfone membranes with pore sizes of 8, 1.2, 0.45, 0.1, and 0.025 μm was employed. Taking into account the ultralow specific concentrations of radionuclides in the water, they were analyzed in 300–500 litre samples using Millipore polysulfone membranes with pore sizes of 0.45 μm and 15 kDa. This allowed us to estimate the percentages of cesium-137 and plutonium-239, 240 in the suspended particulate fraction, colloids, and dissolved species. 相似文献
19.
Doklady Earth Sciences - The approximation of the Earth’s physical surface by a mathematical surface is commonly carried out by a sphere or an ellipsoid of revolution. A triaxial ellipsoid... 相似文献
20.
N. V. Simagin I. O. Murdmaa E. A. Seitkalieva D. G. Borisov E. V. Dorokhova E. M. Emel’yanov O. V. Levchenko 《Lithology and Mineral Resources》2017,52(6):427-434
Facts confirming the hypothesis of contourite sediment infill of the Equatorial Mid-Ocean Canyon (EMOC) are presented. We examined two cores recovered in Cruises 37 and 43 of the R/V Akademik Ioffe (2012, 2013). The cores recovered upper Quaternary miopelagic clays on the EMOC floor (AI-3149) and the adjacent abyssal plain (AI-2620). The study of these cores unraveled significant differences in their composition. In contrast to the lithologically homogeneous Core AI-2620, Core AI-3149 includes interlayers enriched in the biogenic CaCO3, terrigenous silt, and authigenic ferromanganese micronodules. These peculiarities are attributed to activity of the Antarctic Bottom Water (AABW) contour currents along the EMOC. 相似文献