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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.
Solar system
Sources of polarized radiation with unusual spectral features
discovered in the Sun
In the framework of the study of solar active regions that produce
powerful flares the researchers from the RATAN-600 radio telescope
have detected sources with features in the form of a sharp decrease
in the intensity of polarized radiation in various parts of the
recorded frequency range (2-16GHz), sometimes changing the sign
of polarization. Modeling of the phenomenon indicates the presence
of a hot coronal loop at the heights of about 10Mm (the height of
the transition region is about 2-5Mm). The magnetic field strength
of the hot region was measured at 360-450 gauss.
In collaboration with St. Petersburg State University
(Contacts: Bogod V.M.)
Archive of achievements, Solar system sector
Galaxy
New LBV discovered in the Galaxy
As a result of spectroscopy of stars with circular nebulae from the
Spitzer survey (24 microns) on the BTA a new luminous blue variable
star (LBV) was discovered in our Galaxy (MN112). These are very rare
(there are about 10 of them known in the Galaxy) and most massive stars,
locateŚ on the short stage of evolution. The spectra of MN112 and the
famous LBV P Cyg are almost identical. The I-magnitude has increased
by 0.4 over the past 17 years. The absorption of light to the MN112
is 8.4-8.9 mag.
In collaboration with the SAI MSU, the South African Astronomical
Observatory (SAAO)
(Contacts: S.N.Fabrika)
Published: MNRAS, 2010, vol.405, p.520
Flare activity of Cygnus X-3 microquasar from radio waves to
high-energy gamma-radiation
RATAN-600 has registered powerful radio flares from a microquasar
Cygnus X-3. During these flares, hard gamma radiation (AGILE-GRID)
was detected with the energies of > 100 MeV (for the first time from
a star in our Galaxy). It is shown that powerful radio bursts of
the microquasar, which were caused by the ejections of matter at
the speeds close to the speed of light, occur in a certain "super soft"
state of the X-ray radiation (RXTE PCA).
In collaboration with the INAF/IASF-Bologna, Italy; INAF/IASF-Roma,
Italy; the Smithsonian Center for Astrophysics, USA; Cavendish Laboratory,
UK; TKK/Metsohovi Radio Observatory, Finland.
(Contacts: Trushkin S.A.)
From the materials of three works: Nature, 2009, 462, 620-623; MNRAS,
2010, 406, 307-319; A & A, 2011 (submitted)
Speckle interferometry of magnetic stars
We have carried out interferometric observations of a sample 160
chemically peculiar Ap/Bp stars with proven global magnetic fields.
Thirty-eight systems were resolved into individual components. As a
result of our studies, we conclude that, contrary to the current views,
the proportion of double and multiple magnetic stars does not differ
from their non-magnetic counterparts.
(Contacts: Rastegaev D.A.)
Radial gradient of magnetic field in the atmospheres of chemically
peculiar stars
As a result of BTA observations of 23 chemically peculiar stars with
strong magnetic fields, it was found that in 22 of them the longitudinal
magnetic field, measured by the Zeeman shifts in the hydrogen line cores
are systematically lower than the value measured from metal lines.
The observed effect may indicate the presence of a radial gradient
of magnetic field in stellar atmospheres and a more complicated magnetic
field structure than a simple dipole.
(Contacts: I.I.Romanyuk)
Discovery of pulsar pairs - possible components of broken binary systems
Obtaining the radio pulsar trajectories by their kinematic characteristics
distances of closest approach in the past were found for 20 pairs of
rather young objects with measured distances and proper motions. The
analysis of the probability of these encounters revealed that radio
pulsars from 6 pairs could previously be the companions of the binaries
broken up in supernova explosions.
In collaboration SAI MSU
(Contacts: G.M.Beskin)
Archive of achievements, Galaxy sector
Metagalaxy
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.
(Contacts: A.V.Moiseev)
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
(Contacts: D.Makarov)
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.)
Archive of achievements, Metagalaxy sector
Hardware and methodological developments
Archive of achievements, Instrumental and Methodological Development sector
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