Alexander B. Pushkarev
Alexander B. PushkarevLeading researcher at CrAO, Dr. Sci. (physics and mathematics). In 2016 he was appointed a Professor at RAS. A member of IAU.
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Aleksandr Borisovich Pushkarev was born in 1975 in Simferopol. In 1992–1998 – a student in the Department of Astronomy, Faculty of Physics, Lomonosov Moscow State University. In 1998–2001 – a post-graduate student in the Astro Space Center of Lebedev Physics Institute. In 2001 he defended the Ph.D. thesis. In 2002-2015 – a senior researcher at MAO RAS. Since 2004 – a leading researcher at CrAO. Between 2007 and 2010 he worked at the Max Planck Institute for Radio Astronomy (Germany). In 2015 defended his Doctoral thesis in MAO RAS.
Subsequently, applying rich observational material acquired within the wide VLBI-programs (MOJAVE, RDV), ground-space VLBI-observations in cooperation with the Japan satellite VSOP and data taken at the gamma observatory Fermi the following results were obtained: (a) the jet angular apertures were measured and a high degree of their collimation (~1°) was shown, (b) there was experimentally detected an ageing effect of the jet spectral index which was earlier predicted theoretically, (c) a method of measuring frequency shifting of the absolute position of VLBI-nucleus was developed and massively applied for detecting the magnetic field magnitude in a jet and in the vicinity of the central supermassive black hole, (d) the region of gamma-ray emission in active galactic nuclei was localized, and it was shown to be at several parsec distance from the central machine.
In 2009 there was experimentally discovered the predicted in the 1970s effect of multiple quasar radio images formed as a result of anisotropic refractive scattering at the turbulent inhomo-geneities of the intersteller Galaxy medium. The maximum manifestation of the effect was recorded during an especially short phase of extreme scattering event that corresponds to a passage of the lens (screen) edge of high scattering capability on the background compact radio source. The investiga-tions of scattering properties of the interstellar Galaxy medium were carried out using data of VLBI-observations of more than 3 thousand compact extragalactic sources. It was detected that objects observed through the galactic plane (|b|<10°) at 2, 5 and 8 GHz showed an increase in angu-lar sizes, and about one third of them – a significant scattering. These objects were predominantly detected in the direction of the galactic bar, Cygnus region and Fitzgerald window.