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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)
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