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Scientific achievements, Metagalaxy sector


Evidence for the connection between turbulent gas motions and star formation in dwarf galaxies
Observations with the 6-m telescope of SAO RAS have increased by several times the number of dwarf galaxies with constructed ionized gas velocity fields. We show that velocity dispersion is not related to the virial motions in the gravitational potentials of galaxies (a point of view that dominates in the literature), but is determined by the energy "injected" into the interstellar medium with ongoing star formation. This relation has a universal nature in the widest range of galactic masses and luminosities.
(Contact - Moiseev A.V.).
Moiseev A.V. "Ionized gas rotation curves in nearby dwarf galaxies", Astrophysical Bulletin, 2014, Volume 69, Issue 1
Moiseev A.V., Tikhonov A.V., Klypin A.A. "What controls the ionized gas turbulent motions in dwarf galaxies", submitted to MNRAS

Updated Catalog of Nearby Galaxies
A catalog of 869 nearby galaxies (distance < 11 Mpc) was created based on the constantly updated Local Volume galaxy database. This sample is essential for the studies of the formation and evolution of galaxies and structures in the Universe. Only in the Nearby Universe is a detailed study of all the variety of the world of galaxies possible. Approximately 300 galaxies in the sample have high-accuracy distance estimates, allowing one to study the distribution and kinematics of matter on a scale of up to 11 Mpc.
(Contact - Karachentsev I.D.).
Updated Nearby Galaxy Catalog, 2013, AJ, 145, 101

Determination of the mass of a supermassive black hole in AGN Mkn6 based on spectro-polarimetric observations
A unique set of linear polarization measurements in the spectrum of the Seyfert galaxy Mkn6 was obtained with the 6-m telescope. It is shown for the first time that an analysis of the dependence of the polarization angle on the velocity in the hydrogen line profiles, which are determined by the emission of gas in the broad line region (BLR) in the vicinity of the massive AGN, allows to determine directly from observations the type of motion in the BLR, which in the case of Mkn6 proved to be Keplerian at distances less than 0.02 pc from the nucleus. The lower mass limit for the supermassive black hole in AGN Mkn6 was determined as 150 million solar masses.
(Contact - Afanasiev V.L.).

Optical spectroscopy of ultra-luminous X-ray sources (ULX)
Based on the results of optical spectroscopy performed with BTA and Subaru, and on the published data, we discovered that all the ULX objects ever spectroscopically studied have the same rare type of spectrum: WNL or LBV in the hot state. We discovered strong night-to-night emission line variability of up to 350 km/s. Neither a WNL optical star nor an intermediate-mass black hole with a standard disk can explain our optical spectra. The observed spectra correspond to a supercritical accretion disk around a stellar-mass black hole (SS433 type). The investigated ULX objects should have accretion rates onto the black hole 1.5-6 times lower than in the case of SS433.
(Contact - S.N.Fabrika).

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Last update: 18/02/2014