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Scientific achievements, Galaxy sector

 1994: 


Deep CCD images of the bright gamma-ray bursts GRB790418 and GRB790613 localization regions were obtained for the first time. In both cases, a faint blue star-like object (V = 24.5m, BV <0m) was detected within the region of localization of gamma-ray bursts. The observed brightness and color allow to suggest that it may be the compact objects like neutron stars with surface temperatures of about 100 000 K, located at a distance of about 40 pc.
In collaboration with the Astro Space Center of the Physical Institute of RAS.


Based on sixty daily instantaneous spectra of the object SS433, obtained on the RATAN-600 in April-May 1994, we traced its variability in four very powerful flares at five frequencies. The data obtained indicate the generation of relativistic electrons in the flash, emitting in the magnetic fields of the SS433 jets.


Based on the CCD spectra taken with the echelle spectrometers of the 6-m and 1-m telescopes, for the first time a movement of discrete absorption components along the wide wind line profiles of neutral hydrogen and ionized iron was detected in white supergiants. For the 6 Cas supergiant the components were traced back to 200 days, during which time the expansion rate increases up to 180 km/s. It was thus established that the phenomenon of a gusty stellar wind, inherent to a unique object P Cygni, is typical of the cooler stars of maximum luminosity.


Homogeneous determinations of the barium abundance in view of the deviations from the local thermodynamic equilibrium in the atmospheres of 140 stars of the F and G spectral classes in a wide range of metallicities were made. It was found for the first time that the [Ba/Fe] ratio, measured from the resonance line 4554 A, shows dramatic changes near the values of metallicity, corresponding to the boundaries between the halo, the intermediate component and the disc. This result confirms and develops the hypothesis about the active phases of star formation in the history of the Galaxy.
Jointly with the University of Kazan.


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