Influence of accretion-disk models on the structure of the Iron Κ<Subscript>α</Subscript> line

Broad iron Κ_α emission with a characteristic two-peaked profile is observed in most Seyfert galaxies in the X-ray. We have calculated the profiles of such lines emitted by an accretion disk in a Schwartzschild metric. The dependence of the temperature distribution in the disk on the line shape is demonstrated. All the calculations include general relativistic effects. The disk material is assumed to move in circular geodesics in the equatorial plane. The line profile is extremely complex, even in a traditional model for the radial temperature distribution, complicating interpretation of the observational data.     

Possible origins of the diversity of types of Active Galactic Nuclei

The observed variety of types of Active Galactic Nuclei (AGN) in galaxies with various masses and morphologies is considered. It is proposed that this diversity is related to the evolutionary development of their host galaxies and central regions, including their bulges, massive black holes, and accretion disks. A possible evolutionary scenario explaining the relationship between various types of AGN is proposed, in which, in addition to differences in the accretion states of the circumnuclear disks, the type of host galaxy is also taken into consideration. Special attention is given to the qualitative similarity of the accretion and radiative processes occurring in active objects with stellar-mass black holes (microquasars) and in AGN, in spite of the huge differences in the masses of their black holes. Studies of variability of the emission of microquasars taking this similarity into account can be used to make predictions about the behavior of the emission of AGN (with scaling in accordance with the black-hole mass).     

Catalog of Supermassive Black Holes for Interferometric Observations

The paper presents a catalog of supermassive black holes (SMBHs) sharpened for interferometric observations at millimeter and submillimeter wavelengths, based on open sources. The catalog includes the object’s name, coordinates, angular size, and mass, the angular size of the gravitational radius of the SMBH, and the integrated radio flux associated with the radiosource concluding the SMBH at 20?900 GHz, planned for the Event Horizon Telescope, the future space mission Millimetron, and others. The catalog is intended for use during planning of interferometric observations of SMBH shadows.

     

IMAGE INTERPRETATION AS A SYSTEM OF SCIENTIFIC RESEARCH

The article provides insights derived from conceptualization of the totality of elements (subsystems) of image interpretation as part of a larger system of scientific research. Among the elements discussed in some detail in terms of their impacts on the appearance of features interpreted on remote sensing imagery include solar radiation, the atmosphere, distinctive characteristics of the surface of the area being imaged, the remote sensors employed for image recording, processing techniques, the image medium, and the “human” element (interpreter). It then describes an evolutionary process in image interpretation by which knowledge gained in early stages represents an input leading to refinement of approaches employed in later stages. A final section describes factors contributing to dynamics (“scintillation” or “flickering”) of features on imagery of the same area but recorded at different times or under different imaging conditions. Translated by Edward Torrey, Alexandria, VA 22308 from: Izvestiya Akademii Nauk, seriya geograficheskaya, 1993, No. 3, pp. 102-109.     

Analytical approximation for the Fe <Emphasis Type="Italic">K</Emphasis><Subscript>α</Subscript> emission line in quasar spectra

The spectra of many Seyfert galaxies display broad Fe K _α emission. The line profile has two maxima, suggesting that the line emerges in the innermost regions of an accretion disk around a black hole, making it necessary to take into account general relativistic (GR) effects. Identifying GR processes occuring in active galactic nuclei (AGN) requires reconstructing the parameters of the accreting system from the line profile using some reasonably quick algorithm. We present here a numerical approximation for the Fe K _α emission line using analytical functions. The approximation encompasses a range of the disk radial coordinate r and the angle θ between the line of sight and the disk normal, and makes it possible to decrease the computing time by six orders of magnitude in certain astrophysical problems, while taking into account all GR effects. Results of the approximation are available at http://www.iki.rssi.ru/people/repin/approx.     

Gravitational Lensing and Wormhole Shadows

Astronomy Reports - The problem of bending and scattering of light rays passing outside the entrance of a wormhole with zero gravitational mass is considered. The process of ray capture by a...     

The Role of Geomagnetic Anomalies in the O<Superscript>+</Superscript> Concentration Distribution Considering the Seasonal Position of the Sun according to the Data from the Meteor-M Complex

This paper presents an analysis of the mass spectrometry measurement data for the ion composition of the upper atmosphere at altitudes of 810–830 km. A radio frequency mass spectrometer RIMS was mounted on the Meteor-M 1 and 2 spacecraft that were launched in 2009 and 2014. The measurements were carried out by the contact method. The analysis of the seasonal data from January 1, 2016, to January 1, 2017, reveals a seasonal variation in the oxygen ion concentration associated with the Sun’s position. An increase in the O⁺ concentration for the South Pole and a decrease for the North Pole are observed in the regions of magnetic anomalies. The greatest increase in the ion concentration is detected in the region of the Brazilian magnetic anomaly. There are also minor increases in the O⁺ concentration that can be associated with the North American Anomaly over Yellowstone National Park.     

Absence of a periodic component in the quasar z distribution

The presence of a periodic component in the quasar distribution over redshift z is investigated. The periodicity is analysed for the coordinate ln(1 + z) and for the geodesic cosmological distance using the SDSS and 2dF catalogs (??85 000 quasars). Four different criteria and the Fourier transform method were used to search for periodicity. The analysis shows an absence of a periodic component in the quasar redshift distribution at any significant confidence level.     

Protons of Radiation Belts as a Source of Hydrogen in the Earth’s Atmosphere

Doklady Earth Sciences - A scenario is proposed for replenishing the Earth’s exosphere with atomic hydrogen of cosmic origin. An assessment was made, and the coincidence of the total atomic...     

Dielectric spectroscopy of oil-bearing rocks at 0.05–16 GHz

We have measured the dielectric spectra of sand and bentonite mixtures with oil and saline water (NaCl solution) in the frequency range from 50 MHz to 16 GHz at 22 °C. The measured spectra were compared with predictions in terms of the generalized refractive mixing dielectric model (GRMDM), and the respective error was estimated as a check of the model applicability to describe oil-bearing formations. The results may be useful in developing new methods of electromagnetic logging.