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Papers by Nadiia Pulatova

Astronomische Nachrichten

ABSTRACT The new results of studying the general physical properties of the sample of isolated 2M... more ABSTRACT The new results of studying the general physical properties of the sample of isolated 2MIG galaxies with active nuclei (AGNs) with z < 0.05 are presented. The sample was created on the base of a Catalog of isolated galaxies 2MIG and Catalog of AGNs and quasars Veron+2010. We analyzed such parameters as activity type, relative distance to the nearest neighbor - dimensionless parameter 2s, absolute B-band magnitude, galactocentric velocity, bar and rings, morphological type, angular diameter and other. One of the main discussed results relates to the classification of spectral type, namely, Seyfert 2 galaxies are 41% and Seyfert 1 galaxies (with broad lines) are only 10% of the sample. This result may indicate that the isolated AGNs were undergone to the gravitational interaction in the past. It means a close encounter appears capable of activating an evolution sequence where a normal galaxy becomes first a starburst, then a Seyfert 2 and finally a Seyfert 1 galaxy.

Monthly Notices of the Royal Astronomical Society

The host isolated galaxies with active galactic nuclei (AGNs) are unique for recognizing their in... more The host isolated galaxies with active galactic nuclei (AGNs) are unique for recognizing their internal multiwavelength properties and physical parameters of accretion on the supermassive black holes outside of the environment. For detaching these effects, we studied the galaxy sample obtained by cross-matching the 2MIG (2MASS isolated galaxy) catalogue with the Véron-Cetty catalogue of quasars and AGNs, which is limited to Ks ≤ 12.0 mag and Vr 〈 15 000 km s-1. In this paper, we present a full description of 36 2MIG isolated AGNs in the northern sky (δ ≥ -15°). They were classified into several categories (pure and weak isolated AGNs, composites, and with faint companions) to reveal their multiwavelength properties including all the available archived data from literature and data bases. We found that most of the 2MIG northern isolated host galaxies with AGNs belongs to S0-Sc types (about 40 per cent are of Sb type), and a half of them are Sy2-type galaxies; the 2MIG isolated AGNs a...

Proceedings of the International Astronomical Union, Aug 1, 2012

We present the main results of statistical study of general properties of isolated AGN hosts and ... more We present the main results of statistical study of general properties of isolated AGN hosts and AGN hosts in pairs at z < 0.05 as concerns with the environmental influence on the nuclear galaxy activity. With this aim we compiled the sample of 61 isolated AGNs selected from 2MIG Catalog and Catalog Veron+2010, and the sample of 109 AGNs in pairs selected from NED database. We found a significant excess content of Sy 2 type galaxies in comparison with Sy 1 type galaxies in both samples (44 % and 11 % among isolated AGNs, 48 % and 6 % among AGNs in pairs, respectively). Isolated AGN hosts of all spectral types are located, in average, at the more far distances and have a more complicated structure than AGNs in pairs as well as they are mostly of late morphological types. Our statistical analysis shows that the observed nuclear activity of isolated 2MIG AGNs during last 3 billions years and more, first of all, is connected with the internal galaxy parameters (relative mass/size, dark/visible matter content, multiwavelength properties of gas-dust medium in accretion disks, tor's structure, central black hole mass etc.).

EPJ Web of Conferences, 2013

Quasar 3C 279 is known to exhibit episodes of optical polarization angle rotation. We present new... more Quasar 3C 279 is known to exhibit episodes of optical polarization angle rotation. We present new, well-sampled optical polarization data for 3C 279 and introduce a method to distinguish between random and deterministic electric vector position angle (EVPA) variations. We observe EVPA rotations in both directions with different amplitudes and find that the EVPA variation shows characteristics of both random and deterministic cases. Our analysis indicates that the EVPA variation is likely dominated by a random process in the low brightness state of the jet and by a deterministic process in the flaring state.

Monthly Notices of the Royal Astronomical Society, 2015

The isolated galaxies are the ideal astrophysical laboratory for distinguishing the properties of... more The isolated galaxies are the ideal astrophysical laboratory for distinguishing the properties of other galaxies passed the evolution in environment. The host isolated galaxies with AGNs are unique in this sense due to recognize their internal multi-wavelength properties as well as the physical parameters of accretion on the central supermassive black holes outside of the environment effects.

Monthly Notices of the Royal Astronomical Society, 2013

ABSTRACT Since the launch of the Fermi satellite, BL Lacertae has been moderately active at γ-ray... more ABSTRACT Since the launch of the Fermi satellite, BL Lacertae has been moderately active at γ-rays and optical frequencies until 2011 May, when the source started a series of strong flares. The exceptional optical sampling achieved by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope in collaboration with the Steward Observatory allows us to perform a detailed comparison with the daily γ-ray observations by Fermi. Discrete correlation analysis between the optical and γ-ray emission reveals correlation with a time lag of 0 ± 1 d, which suggests cospatiality of the corresponding jet emitting regions. A better definition of the time lag is hindered by the daily gaps in the sampling of the extremely fast flux variations. In general, optical flares present more structure and develop on longer time-scales than corresponding γ-ray flares. Observations at X-rays and at millimetre wavelengths reveal a common trend, which suggests that the region producing the mm and X-ray radiation is located downstream from the optical and γ-ray-emitting zone in the jet. The mean optical degree of polarization slightly decreases over the considered period and in general it is higher when the flux is lower. The optical electric vector polarization angle (EVPA) shows a preferred orientation of about 15°, nearly aligned with the radio core EVPA and mean jet direction. Oscillations around it increase during the 2011-2012 outburst. We investigate the effects of a geometrical interpretation of the long-term flux variability on the polarization. A helical magnetic field model predicts an evolution of the mean polarization that is in reasonable agreement with the observations. These can be fully explained by introducing slight variations in the compression factor in a transverse shock waves model.

Astrophysics, 2008