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Scientific achievements, Galaxy sector

The character of internal motions of gas in 7200 HI clouds in the outer region of our Galaxy was investigated according to the data of the HI survey with the RATAN-600. It turned out that the effect of turbulence, as the main mechanism of gas motion is not essential, while it was discovered that 36% of the clouds are rotating. The distribution of the axes of rotation of clouds in space is random, which leads to the conclusion that the collision of clouds is the main source of their rotation.

Periodic variations of optical emission of the gamma, X-ray and radio pulsar GEMINGA were for the first time discovered from the observations with the BTA. Its luminosity amounts to 26.0+/-0.4^m in the B-band, i.e. it is the weakest of the known optical pulsars. The light curve of the object consists of two pulses, the phases of which coincide with the pulse phases in the gamma range, and its shape is consistent with the assumption about the 100% modulation, indicating the non-thermal origin of the overwhelming proportion of optical radiation.
(Jointly with the Holloway College, Ireland.)

According to the observations in the radio 21cm on the RATAN-600 revealed two expanding shell of interstellar gas, one of which is surrounded by an extended thermal radio source Cygnus X, other, smaller diameter, is situated around the remains of a supernova star in this complex. The physical parameters of the membranes and determine their nature. Score ages of shells in their kinematics shows that star formation in this area can be triggered by the shock wave from the stellar wind-rich stellar association Cyg OB2.

During the 80-day RATAN-600 monitoring in the framework of study of galactic X-ray binary systems at six frequencies (1.38-31cm) several radio flares in Cyg X-3 were first reported. A significant anticorrelation of the level of soft X-ray and radio flux during a powerful burst on June 12, 1997 was discovered, while in the quiet period its X-ray and radio emissions are correlated. A deep preflare flux drop during 10 days before the powerful flare is apparently due to the temporary disappearance of the jets. At the beginning of the outbreak the emission process is dominated by the inverse Compton effect at the generated relativistic particles. The flare fades during the subsequent adiabatic expansion of the jets.

As a result of spectroscopic observations with the BTA it was shown that a peculiar hypergiant IRC 10420, having a powerful infrared radiation, has changed the effective temperature of its atmosphere from 6000 to 8500K over the past 20 years, and is observed in the rarely observed transition stage to a Wolf-Rayet-type star.

In the process of implementation of the BTA spectroscopic survey of star-like objects from the IRAS catalogue, a number of objects were discovered to have a new type of optical spectra - molecular emissions arising in circumstellar envelopes by a mechanism of resonance fluorescence.

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