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Detection of a Very Slow Magnetic Rotator HD 965
Based on the measurements of the magnetic field of the chemically peculiar star HD 965,
conducted in 2000-2015 with the SAO RAS 6-m telescope, we have found that this object is an
ultraslow magnetic rotator with a rotation period of about 20 years. HD 965 is one of the three
very slow rotators among more than 300 studied CP stars. Thus, very slow rotation is a very rare
but not unique phenomenon. The occurrence of three such rotators means that the dynamo
mechanism is not efficient during the life of a peculiar star on the main sequence and cannot
generate a large-scale magnetic field. The generation occurs at early evolutionary stages before
the arrival of the star on the main sequence.
Authors:
I.Romanyuk ,
D.Kudryavtsev, E.Semenko, I.Yakunin
Published:
I.Romanyuk, D.Kudryavtsev, E.Semenko, I.Yakunin, Magnetic Field Monitoring of the
Very Slowly Rotating CP Star HD 965, 2015, Astrophysical Bulletin, 70, 4, 482
Detection of a Uniquely Bright Radio Flare in the X-Ray Binary
Star with a Black Hole V404 Cygni (GS2032+336)
The optical nova and X-ray binary V404 Cyg, consisting of a black hole
with a mass of 10M☼
and a K0 subgiant with a mass of 0.6M☼ which fills its
Roche lobe, was studied from June 18 to
July 12, 2015 with the RATAN-600 radio telescope in the range from 2.3 to
22 GHz. In this
period, the V404 Cyg radio spectrum was cardinally changing along with
the flux measurements
in the range of 15-300 keV (Swift/BAT and Integral). On June 26, two hours
later an X-Ray flare
of 50 Crab, the radio flux increased 40 times up to 4 Jy per day. It was
concluded that it was the
very beginning of the formation of a relativistic jet ejection from
the poles of the accretion disk
at the time of near-critical accretion of matter on the black hole.
Authors:
S.Trushkin,
N.Nizhelskij, P.Tsybulev
Published:
1. Trushkin S.A., Nizhelskij N.A., Tsybulev P.G, The Inverted Radio Spectrum of the Flare
in V 404 Cyg, The Astronomer's Telegram, 2015, #7667
2. Trushkin S.A., Nizhelskij N.A., Tsybulev P.G., A New Giant Radio Flare of V404 Cyg at
Centimeter Wavelengths, The Astronomer's Telegram, 2015, #7716
Detection of an OH Maser Flare in the Nebula W3
Observing OH masers at a frequency of 1665 MHz in the source W3(по) with
the 32-m antenna
of the Svetloe Radio Astronomy Observatory (IAA RAS), we detected a
radiation burst in the
right circular polarization at a radial velocity of -46.2 km/s at UT 03:27
on January 23, 2012. At
that moment, the radiation flux increased 7 times in 90 seconds and then
decreased down the
previous level. Such a time gives an estimate of the maser spot linear
dimension of 0.18 AU
(2.7X1012 cm). In 2013-2014, we found intensity variations of
the components at -47.6 and
-45.1 km/s with characteristic times of the order of 10 hours, moreover,
the variations of the
right and left polarization fluxes were evidently anticorrelated. Such
phenomena in the OH
maser research are discovered for the first time and have not been
explained by any maser variability models.
Authors:
I.Gosachinskij,
ogether with S.Grenkov, A.Ipatov, I.Rakhimov (IAA RAS)
Published:
The results were reported at the 32th All-Russian Conference "Actual Problems of Extragalactic
Astronomy", April 20-23, 2015, Pushchino, and at the 13th Russian-Finnish Symposium on
Radio Astronomy, May 25-29, 2015, Saint Petersburg,
I.Gosachinskij, S.Grenkov, A.Ipatov, I.Rakhimov, An OH Maser Flare in the Nebula W3,
"Astronomy Letters", submitted to the journal.
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