M. L. Khabibullina
Russian Academy of Sciences
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by M. L. Khabibullina.
Astrophysical Bulletin | 2009
O. V. Verkhodanov; M. L. Khabibullina; E. K. Majorova
We offer a method of correlations mapping on the full celestial sphere that allows to check the quality of reconstructed maps, their non-Gaussianity and conduct experiments in various frequency ranges. The method was evaluated on the WMAP data, both on the reconstructed maps and foreground components, and on the NRAO VLA Sky Survey (NVSS) data. We detected a significant shift in the correlation data of the dust component, which can be preconditioned by a more complex dust model than the one currently in use for component separation. While studying the NVSS correlation data, we demonstrated that the statistics of the coinciding spots in the microwave background and in the NVSS survey corresponds to the one expected in the ΛCDM model. This can testify for a chance coincidence of the spots in the NVSS and WMAP data in the CMB Cold Spot region. Our method is software-implemented in the GLESP package. PACS: 95.75.-z, 98.62.Ve, 98.70.Dk, 98.70.Vc, 98.80.-kWe offer a method of correlations mapping on the full celestial sphere that allows to check the quality of reconstructed maps, their non-Gaussianity and conduct experiments in various frequency ranges. The method was evaluated on the WMAP data, both on the reconstructed maps and foreground components, and on the NRAO VLA Sky Survey (NVSS) data. We detected a significant shift in the correlation data of the dust component, which can be preconditioned by a more complex dust model than the one currently in use for component separation. While studying the NVSS correlation data, we demonstrated that the statistics of the coinciding spots in the microwave background and in the NVSS survey corresponds to the one expected in the ΛCDM model. This can testify for a chance coincidence of the spots in the NVSS and WMAP data in the CMB Cold Spot region. Our method is software-implemented in the GLESP package.
Astrophysical Bulletin | 2010
O. V. Verkhodanov; M. L. Khabibullina
The method of correlation mapping on the full sphere is used to study the properties of the ILC map, as well as the dust and synchrotron background components. An anomalous correlation of the components with the ILC map in the main plane and in the poles of the ecliptic and equatorial coordinate systems was discovered. Apart from the bias, a dominant quadrupole contribution in the power spectrum of the mosaic correlation maps was found in the pixel correlation histogram. Various causes of the anomalous signal are discussed.The method of correlation mapping on the full sphere is used to study the properties of the ILC map, as well as the dust and synchrotron background components. An anomalous correlation of the components with the ILC map in the main plane and in the poles of the ecliptic and equatorial coordinate systems was discovered. Apart from the bias, a dominant quadrupole contribution in the power spectrum of the mosaic correlation maps was found in the pixel correlation histogram. Various causes of the anomalous signal are discussed.
Astrophysical Bulletin | 2009
M. L. Khabibullina; O. V. Verkhodanov
The procedure of the construction of a sample of distant (z > 0.3) radio galaxies using NED, SDSS, and CATS databases for further application in statistical tests is described. The sample is assumed to be cleaned from objects with quasar properties. Primary statistical analysis of the list is performed and the regression dependence of the spectral index on redshift is found.
Astrophysical Bulletin | 2010
O. V. Verkhodanov; V. V. Sokolov; M. L. Khabibullina; Sergey Karpov
We analyze the randomness of the sky distribution of cosmic gamma-ray bursts. These events are associated with massive galaxies, spiral or elliptical, and therefore their positions should trace the large-scale structure, which, in turn, could show up in the sky distribution of fluctuations of the cosmicmicrowave background (CMB). We test this hypothesis by mosaic correlation mapping of the distributions of CMB peaks and burst positions, find the distribution of these two signals to be correlated, and interpret this correlation as a possible systematic effect.
Astrophysical Bulletin | 2011
M. L. Khabibullina; O. V. Verkhodanov; M. Singh; A. Pyria; S. Nandi; N. V. Verkhodanova
We report the results of flux density measurements in the extended components of thirteen giant radio galaxies, made with the RATAN-600 in the centimeter range. Supplementing them with the WENSS, NVSS and GB6 survey data we constructed the spectra of the studied galaxy components. We computed the spectral indices in the studied frequency range and demonstrate the need for a detailed account of the integral contribution of such objects into the background radiation.
Astronomy Reports | 2010
M. L. Khabibullina; O. V. Verkhodanov; M. Singh; A. Pirya; N. V. Verkhodanova; S. Nandi
Measurements of the flux densities of the extended components of seven giant radio galaxies obtained using the RATAN-600 radio telescope at wavelengths of 6.25 and 13 cm are presented. The spectra of components of these radio galaxies are constructed using these new RATAN-600 data together with data from the WENSS, NVSS, and GB6 surveys. The spectral indices in the studied frequency range are calculated, and the need for detailed estimates of the integrated contribution of such objects to the background emission is demonstrated.Measurements of the flux densities of the extended components of seven giant radio galaxies obtained using the RATAN-600 radio telescope at wavelengths of 6.25 and 13 cm are presented. The spectra of components of these radio galaxies are constructed using these new RATAN-600 data together with data from the WENSS, NVSS, and GB6 surveys. The spectral indices in the studied frequency range are calculated, and the need for detailed estimates of the integrated contribution of such objects to the background emission is demonstrated. PACS: 98.54.Gr, 98.62.Ai, 98.70.Dk, 98.70.Vc
Astronomy Reports | 2016
O. V. Verkhodanov; E. K. Maiorova; Olga P. Zhelenkova; D. I. Solov’ev; M. L. Khabibullina
Fields of the Planck cosmic-microwave background maps in the regions of radio sources of the RCR catalog have been studied. Using measurements from the Planck catalog, calibration curves have been plotted in order to determine the objects’ luminosities. The flux densities at millimeter and submillimeter wavelengths of 83 objects with normal radio spectra have been estimated for the first time; their spectra have also been constructed, they have been optically identified, and information available in various databases has been collected. A statistical comparison with a sample of sources with steep radio spectra has been carried out. Faint, difficult to characterize microwave sources make an additional contribution to the secondary anisotropy on angular scales < 7′. An algorithm for selecting candidate objects with the Sunyaev–Zel’dovich effect has been proposed, based on the use of data on the radio spectral indices and the signal in cosmic-microwave background maps.
Astrophysical Bulletin | 2015
O. V. Verkhodanov; E. K. Majorova; Olga P. Zhelenkova; M. L. Khabibullina; D. I. Solovyov; Yu. N. Parijskij
We have studied the regions of the microwave background radiation maps of the Planck experiment in the neighborhood of the RCR catalog radio sources. From the processed data for bright radio sources in the microwave range, we plotted the calibration curves which allow the brightness of the objects to be measured. For the first time, for 117 objects we obtained estimates of flux density at the millimeter and submillimeter waves, prepared the spectra, conducted identification, and gathered available information from databases. Faint microwave sources, difficult to clear out, additionally contribute to the secondary anisotropy at angular scales smaller than 7′.
Astrophysical Bulletin | 2009
M. L. Khabibullina; O. V. Verkhodanov
We describe the procedure of the construction of a sample of distant (z > 0.3) radio galaxies using the NED, CATS and SDSS databases for further use in various statistical tests. We believe the sample to be free of objects with quasar properties. This paper is the third part of the description of the radio galaxies catalog that we plan to use for cosmological tests. We report the results of the sample of angular sizes for the NVSS survey list objects, and its preliminary statistical analysis. Three-parameter diagrams “angular size-redshift-flux density” and “angular size-redshift-spectral index”, and their two-parameter projections are constructed. Three subsamples of radio galaxies are separated in the “source size-flux density” diagram.
Astrophysical Bulletin | 2016
O. V. Verkhodanov; D. I. Solovyov; O. S. Ulakhovich; M. L. Khabibullina
Applying the stacking method, we examine the areas of the cosmic microwave background radiation (CMB) maps, constructed according to the Planck SpaceObservatory data in the neighbourhood of different populations of radio sources and giant elliptical galaxies. The samples of objects include giant radio galaxies (GRG), radio sources, selected by the radio-spectral index and redshift, as well as the gamma-ray bursts, used as a secondary comparative sample. We have studied the topological properties of the CMB signal in the neighbourhood of the average object of the population, namely, we searched for the presence of the maxima and minima in the average area. The difference of the signal in the neighbourhood of GRGs from the other types of objects was discovered.