Here you would find a brief summary of the most important results of
scientific research carried out by our researchers during the last year,
presented by the observatory to the Department of Physical Sciences
of the RAS.
Access here the archives of our results from 1993.
Quasi-Periodic Pulsations (QPPs) in Solar Micro Flares
From polarized spectroscopic observations at RATAN-600 on January 25, 2017, we detected a strong "micro flare" with QPPs; it was unnoticed by the global solar monitoring stations working in various ranges. A characteristic feature of the spectrum lies in the fact that the gradual increase of flux with wavelength was followed by an abrupt explosive brightening in the range of 3-4 GHz tens times greater than the brightness of the quiescent Sun. Studies of the time evolution and comparison with EUV (extreme UV) showed that this type-B2 micro flare was initiated by the appearance of an S-like loop. The polarized radio emission from this micro flare observed at RATAN-600 was generated by non-thermal electrons, whose hard X ray emission was detected with the RHESSI space mission. The result is unique, as the limiting parameters combined the space and ground-based observation complexes and a rare flash event with a new radiation mechanism was detected.
Authors: Nakariakov V.M. (SAO RAS, the University of Warwick, GB), Anfinogentov S. (ISTP SB RAS), Storozhenko A.A. (SAO RAS), Kurochkin E.A. (SAO RAS), Bogod V.M. (SAO RAS), Sharykin I.N. (OFMZ SB RAS, IKI RAS), Kaltman T.I. (SAO RAS).
1. Nakariakov, V.M., Anfinogentov, S., Storozhenko, A.A., Kurochkin, E.A., Bogod, V.M., Sharykin, I.N., Kaltman, T.I., Quasi-periodic pulsations in a solar microflare, Astrophys. J. 859, 154, 2018
2. V.M. Bogod, T.I. Kaltman, A.A. Pervakov, Yu.V. Sotnikova, S.A. Trushkin (SAO RAS, Russia) Solar powerful short-term flare in NOAA12628 at 3-4 GHz on 25 Jan 2017, 10:16:43 UT ATel #10011; on 27 Jan 2017; 13:32 UT .
Archive of achievements, Solar system sector
Radius of the M giant IRC+00213 Measured for the First Time
Direct measurements of stellar radii regardless of other fundamental properties are a complex issue of observational astrophysics. The number of stars available for these measurements is limited due to small angular sizes of disks and also to technical and methodological difficulties. The radii considerably vary for different types of stars and are unique for objects of a certain type. The diameter of the M giant IRC+00213 was measured at the 6-m BTA telescope of the Special Astrophysical Observatory of RAS with the method of lunar occultations. Observations were carried out in the night of April 25-26, 2018 with the speckle interferometer at the 6-m BTA telescope in the pseudo-continuum region at a wavelength of 694 nm. This region of the visible spectrum is sparsely populated with titanium-oxide molecular bands typical of such kind of stars. This shows that the obtained value is close to photospheric. The measured angular diameter from a model of a uniformly luminous disk yielded 2,23±0,06 millisecond of arc. It agrees well with an empirical estimate of 2,14±0,13 millisecond of arc based on magnitude and color (van Belle, 1999).
Authors: Dyachenko V.V., Balega Yu.Yu., Beskakotov A.S., Maksimov A.F., Mitrofanova A.A., Rastegaev D.A. (SAO RAS), Richichi A. (Osservatorio Astrofisico di Arcetri, Firenze, Italy).
1. Dyachenko, V., Richichi, A., Balega, Y., Beskakotov, A., Maksimov, A., Mitrofanova, A., & Rastegaev, D. Lunar occultation observations at the SAO RAS 6-m telescope. 2018. Monthly Notices of the Royal Astronomical Society, 478(4), pp. 5683-5688.
Archive of achievements, Galaxy sector
Detection of the Direction of Polarization Vector in the Intraday
Variations of the Source S5 0716+714
In February 2018, we monitored the variations of brightness and polarization of the bright radio source S5 0716+714 (a BL Lac object) at the 6-m BTA telescope of SAO RAS. The procedure of observations, implying measurements of three Stokes parameters (I, Q, and U) of the polarized emission allowed us to achieve the accuracy of polarimetric measurements better than 0.1%. The analysis of a number of observations obtained within 9 hours with a time resolution of about 70 seconds showed the presence of variability of the integrated brightness and the direction of the polarization vector at times of about 1.5 hours. Assuming that the optical polarized synchrotron emission of the jet is generated in a spiral magnetic field at a distance of less than 0.01 parsec from the nucleus, a linear size estimate of the radiating region of the order of 10 AU was obtained. The numerical simulation of the observed polarization in the jet also showed the presence of a precessing spiral magnetic field with a precession period of about 15 days.
Shablovinskaya E.S., Afanasiev V.L. (SAO RAS).
1. E.S. Shablovinskaya, V.L. Afanasiev The intraday variations of polarization vector direction in radio source S5 0716+714, 2019, MNRAS, Volume 482, Issue 4, p.4322-4328
Detection of the System of Gaseous Clouds Illuminated by the Active
Nuclei of the Galaxy Mrk 6
We studied the distribution, motions, and state of gas ionization in the galaxy Mrk6 at the 6-m SAO RAS telescope. In the emission lines of the ionized gas, extended filaments were found far beyond the galactic disk up to 40 kpc from the nucleus. Such a gas system is unique among nearby isolated galaxies. All the obtained data can be explained in the assumption that the observed gas is captured from the intergalactic medium and illuminated by hard radiation of the active galactic nucleus. Thus, the active core appeared to be a kind of "searchlight" which made it possible to directly observe the capture of low-density gas by the galaxy. Deep images obtained at the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory of the National Academy of Sciences (Armenia) show the absence of any star structures (tidal tails, destroyed satellites) associated with gaseous filaments.
Smirnova A.A., Moiseev A.V., Dodonov S.N. (SAO RAS).
Smirnova A.A., Moiseev A.V., Dodonov S.N., "A close look at the well-known Seyfert galaxy: extended emission filaments in Mrk 6", 2018, MNRAS, v. 481, p. 4542.
Compiling a Catalog of Nearby Voids and Galaxies in them
Voids are elements of the cosmic web visible in the matter distribution. They occupy more than 75% of the Universe but contain only 15% of its mass. The observed properties of voids and galaxies inhabiting them are important for comparison with predictions of formation and evolution of structures in modern cosmological models. We compiled the first catalog of 25 nearby voids (at distances of up to 25 Mpc) covering the whole celestial sphere. The voids with sizes from 14 to 35 Mpc are limited by large galaxies with the infrared luminosity greater than 20 billion L(solar)_K. We compiled a sample of 1354 galaxies inhabiting these voids. Their "blue" (B) luminosities fall in the range of 0.2 million-7 billion L (solar) _B, with a median value of about 100 million. We found that 1088 objects are "internal" galaxies of voids with distances to large galaxies of more than 2 Mpc. This sample of void galaxies is basic for more detailed studies of both the properties of galaxies and the structure of voids. We described statistical properties of galaxies of nearby voids including morphology and the proportion of early-type galaxies, clustering, and gas abundance. We showed the opportunities of the new sample to search for unusual, youngest galaxies of the nearby Universe.
Pustilnik S.A., Tepliakova A.L., Makarov D.I. (SAO RAS).
1. Pustilnik S.A., Tepliakova A.L., Makarov D.I., «Void galaxies in the nearby Universe. I. Sample description», 2019, MNRAS, Volume 482, Issue 4, p.4329-4345
Archive of achievements, Metagalaxy sector
Hardware and methodological developments
Introduction of Fast Radiometry at RATAN-600 for Studying Pulsar Radiation
The mode of fast radiometry with a discretization interval from 60 to 490 μs was implemented at the RATAN-600 radio telescope at a frequency of 4.7 GHz. For the first time ever, we detected single impulses from the close pulsar PSR0329+54 in the Southern sector and the young pulsar PSR0534+22 in the Crab Nebula in the Western sector. In the survey on the search for fast radio outbursts at the Western sector, we detected five single giant impulses (GI) from the 33-millisecond pulsar PSR0534+22 in the Crab Nebula at a multipath spectral complex with high temporal resolution in the 4.2-4.8 GHz frequency band. On June 30, 2018, the flow of GI (∼1 ms) exceeded 150 Jy, while the average impulse flows are below 10 mJy. From the time shift of the impulse arrival the dispersion was measured: DM = 57±1 pc/cm3 which is in good agreement with previous measurements. The GI detected in observations on October 2, 2018 consisted of two sub-impulses with a flux of about 8 and 4 Jy and a duration of 300 μs separated by 400 ms. It follows that the area of impulse radiation has a size of about 100 km, and its brightness temperature exceeds 1025 K. Using the fast radiometry mode and the "source-tracking" mode for 100-200 s will allow us to determine average fluxes and impulse profiles of pulsars at 4.7 GHz with the RATAN-600 radio telescope.
Authors: Trushkin S.A., Tsybulev P.G., Bursov N.N., Nizhelskij N.A. (SAO RAS).
Integrated Information System to Maintain Observations at SAO RAS Telescopes
Authors: VitkovskijV.V., Plyaskina T. A., Zhelenkova O.P., Shergin V. S. (SAO RAS).
Archive of achievements, Instrumental and Methodological Development sector
Archive of achievements, Astronomical education sector