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.
Archive of achievements, Solar system sector
Super slow rotators as a test of stellar magnetic field formation mechanisms
As a result of long-term observations at the 6-m BTA telescope, it was proved that super slow magnetic rotators (stars with rotation periods of more than several years and strong magnetic fields) are not an exception, as was previously believed, but a natural phenomenon among magnetic Ap stars. The presence of such objects proves that a magnetic field in Ap stars of the Main Sequence can exist for a long time without any generation by the dynamo mechanism. Thus, this mechanism is not a necessary condition for the existence of a magnetic field. The result is important for the theory of the formation of stellar magnetic fields, as it clearly shows that to explain their existence in the stars of the upper part of the Main Sequence, the hypothesis of the fossil origin of a field (from the magnetic field of the protostellar nebula or generation in the early stages of evolution) is enough.
Authors: Romanyuk I.I., Kudryavtsev D.O., Semenko E.A., Yakunin I.A. (SAO RAS)
Detection of linear increase of radio emission from the microquasar
Cygnus X-3 during the giant flare in June 2019
During the studies of the flare of the microquasar Cygnus X-3, when for a while it became the brightest stellar radio source in the Milky Way, in a series of measurements on the multi-azimuth antenna system of the RATAN-600 radio telescope to track the object for five hours, we established for the first time in the world that at the very beginning of the event (June 18, 2019), the brightness of the radio source grew linearly and faster with time at higher frequencies. This may be a decisive moment for determining the mechanism of generation of relativistic electrons in jet emissions of the microquasar.
Authors: Trushkin S.A., Bursov N.N., Shevchenko A.V., Tsybulev, P.G., Nizhelskij N.A., Kudriashova A.A., Borisov A.N., Bogod V.M., Storozhenko A.A. (SAO RAS)
1. S.A. Trushkin, N.A. Nizhelskij, P.G. Tsybulev, A.V. Shevchenko, Cygnus X-3 entered in the quenched radio and hard X-ray stat, http://www.astronomerstelegram.org/?read=12510
2. S.A. Trushkin, N.A. Nizhelskij, P.G. Tsybulev, N.N. Bursov, A.V. Shevchenko, Evolution of multi-frequency emission from Cygnus X-3 in the current giant flare, http://www.astronomerstelegram.org/?read=12701
3. S.A. Trushkin, N.A. Nizhelskij, P.G. Tsybulev, N.N. Bursov, A.V. Shevchenko, А.A. Kudriashova, A.N. Borisov Gaint flares of the microquasar Cygnus X-3, RAA, 2020, 4pp submitted
Archive of achievements, Galaxy sector
Observed characteristics of globular clusters in the ultra-diffuse dwarf galaxy IKN
As a result of observations at BTA in a long-slit mode with the SCORPIO-1 instrument (Afanasyev and Moiseev 2005), the spectra were obtained and radial velocities, age, metallicity, and abundances of chemical elements Mg, Ca, and C were determined for the first time for 4 globular clusters in the closest representative of the rarest class galaxies - the ultra-diffuse dwarf galaxy (UDG) IKN - located at a distance of 3.75 Mpc. UDGs have diameters of the order of several kiloparsecs and very low surface brightness. They consist of old stars. Globular clusters in IKN turned out to be old and low-metal, similar in chemical abundance to NGC6341 in the Milky Way. The results of this work are important for understanding the properties of stellar populations of IKN and verifying the presence of the dark matter in the UDG.
Authors: Sharina M.E. (SAO RAS), Shimansky V.V. (KFU)
1. Sharina M.E., Shimansky V.V. «Globular cluster spectroscopy in the spheroid dwarf galaxy IKN», 2019, Astronomical Journal, Volume 96, No. 8, p. 674-686
Chemical composition of gas in polar-ring galaxies
In galaxies with polar rings, outer rings of stars, gas, and dust are observed rotating almost perpendicular to the disk of the central galaxy. This peculiar morphology is the result of gravitational interaction with the matter of a different direction of the rotation momentum. This can be a merger with an orthogonally oriented companion, capture of the dwarf companion matter, or gas accretion from extended cosmological filaments. The last scenario is gaining more and more popularity, but accurate measurements of the chemical composition of gas are necessary to verify it, since the theory predicts a relatively low abundance of heavier elements in it. As a result of spectroscopic studies carried out at the 6-m SAO RAS telescope, the number of galaxies with polar rings with measured oxygen abundance was three times increased. Moreover, all galaxies follow the standard "luminosity-metallicity" ratio, which rejects for them the scenario of the formation of polar structures by accretion from filaments. It is also shown that a significant role in gas ionization is played by shock waves arising from the collision of gaseous clouds of the ring and the stellar disk of the galaxy. This effect has long been predicted but was previously observed only in a single galaxy.
Authors: O.V. Egorov, A.V. Moiseev (SAO RAS, SAI MSU)
1. O.V. Egorov, A.V. Moiseev, Metallicity and ionization state of the gas in polar-ring galaxies, 2018, MNRAS, v. 486, p. 4186
Archive of achievements, Metagalaxy sector
Hardware and methodological developments
Wide-format CCD systems with high sensitivity in the red spectrum
Two cryostatic digital image recording systems based on wide-format thick-plate CCD photodetectors CCD231-84 (4128 x 4112 elements) and CCD261-84 (2080 x 4112 elements) (Teledyne E2V, Great Britain) were implemented and ready for operation at the BTA. The photodetectors are highly sensitive in the red and near-infrared ranges. In particular, at a wavelength of 900 nm, the quantum efficiency of the receivers is 60% (CCD231-84) and 90% (CCD261-84), compared to 30% for the thin CCDs that are currently used in BTA observations. The DINACON-5 last-generation universal controller is used in CCD systems, thanks to which a low readout noise (2.3 e–) is achieved, which is 20% better than the passport specifications. The high sensitivity of photodetectors in combination with low noise systems makes it possible to obtain more reliable observation data in the red region of the spectrum and to reduce the exposure time, which leads to saving the telescope time. The development and production of systems of this type at SAO RAS are unique in the Russian Federation. The performed work lays the foundation for the complete update of the BTA-telescope CCDs.
Authors: Murzin V.A., Ardilanov V.I., Afanasieva I.V., Ivashchenko N.G., Pritychenko M.A., Borisenko A.N. (SAO RAS)
Ardilanov V.I., Murzin V.A., Markelov S.V., Afanasieva I.V., Ivashchenko N.G., Mitiani G.Sh., Pritychenko M.A., Borisenko A.N. A new generation CCD controller for the 6-meter telescope // Astronomy: Cognition Without Borders: Abstracts of VAK-2017, September 17-22, 2017, Yalta, Crimea, Russia, p. 33.
High-precision and quick alignment of large antenna surfaces
A high-precision method for the quick alignment of large antenna surfaces was developed and introduced in the standard mode using the example of geodetic alignment of the Southern sector and the RATAN-600 Flat reflector. The essence of the method is to fit the software and operating modes of the Leica TDRA6000 tacheometer to the conditions and surface requirements of the RATAN-600 radio telescope. The advantage of the method is the accuracy (0.5 arcsec, 0.2-0.35 mm in the center and at the edges of the sector, respectively), speed (2-3 hours), and large-scale measurements (up to 600 m). The method was effectively tested for the Southern sector and the RATAN-600 Flat reflector in 2019. The figure shows the measurement scheme of the radio telescope network and the state of some elements of the Southern sector during alignment. The method is also relevant for quick assessment of the state of the antenna surface.
Authors: Zharov V.I., Boyko A.A., Kornienko I.B., Sotnikova Yu.V.
Development of a technique for applying reflective coatings to multi-purpose
large-sized optical instruments
The results of the method of applying reflective coatings to multi-purpose large-sized optical instruments are presented. The technique was developed with reference to the VUAZ-6 vacuum chamber. In order to achieve repeatability of the result, total redesign of the camera evaporation system was carried out. Comparative characteristics of the technological processes are given. The results are presented as functions of the reflection coefficient of the BTA main mirror surface from the wavelength. We indirectly estimated the thickness of the obtained layers and their morphology. SAO RAS has the modern vacuum instrument which is unique in Russia used for applying reflective coatings on objects of various purposes with a diameter of up to 6 meters.
Authors: Yakopov G.V.
Archive of achievements, Instrumental and Methodological Development sector
Archive of achievements, Astronomical education sector