Traces of recent interactions in active isolated galaxies
Extensive tidal envelopes surrounding a number of active (Seyfert) galaxies, which were previously considered to be not interacting were discovered on the BTA. It is shown that in a sample of active isolated galaxies about 35% have undergone a merger with another galaxy during the last 0.5-1 billion years. It is noted that statistical studies, based on the digital sky surveys lead to an underestimation of the proportion of small mergers among the galaxies with active nuclei.
Posted: MNRAS, vol.408, p.400, 2010.
Study of star formation in dwarf galaxies
The history of star formation in dwarf galaxies outside the Local Group (KDG61 and KDG64 in the M81 group of galaxies) was analyzed for the first time. The BTA spectra and direct imaging form the Hubble Space Telescope were used, yielding consistent results. Both galaxies are dominated by old stellar population (12-14 million years) of low metallicity ([Fe/H] ~ -1.5), 1.4 billion year old stars with a slight enrichment by metals are as well present. No radial gradient in age and metallicity of the stellar population was found.
In collaboration with the Observatory of Lyon, France
Study of radio spectra and variability of GPS-sources
The RATAN-600 studies have confidently identified 33 GPS (Gigahertz Peaked Spectrum) sources. A steeper drop was detected in the electron energy distribution for the GPS-galaxies, rather than for the GPS-quasars - the difference of the exponent is of about 0.46. The "steepening" of the galaxy spectra is possibly due to additional (with regards to quasars) aging-linked energy losses for radiation, or the sample galaxies may have been born later than quasars (at small z) and there exists a cosmological difference in the energy spectra of electrons.
In collaboration with the Metsahovi Radio Observatory
(Contacts: Mingaliev M.G.)