the Russian Academy of Sciences (RAS), Dmitrii Aleksandrovich Varshalovich, well known for his studies in the field of quantum theory, radiation theory, physics of interstellar matter, quasar physics and cosmology, passed away on April 21 at the age of 86. Varshalovich was born in 1934 in Leningrad into the family of a prominent entomologist, Aleksandr Aleksandrovich Varshalovich, and a biologist, Vera Yakovlevna Skurikhina. In 1941, when a child, he was evacuated from Leningrad, where he returned with his mother in 1944. In 1952, he finished school with a gold medal and entered the physical faculty of Leningrad State University. He graduated from the University in 1957 as a specialist in nuclear spectroscopy and joined the laboratory of nuclear isomerism of the Leningrad Physical-Technical Institute (LPTI, now Ioffe PTI). Within several years, he carried out a series of studies in nuclear isomerism and nuclear spectroscopy, collaborating with L I Rusinov and L K Peker. Those same years, together with I V Kurcharov and Rusinov, he wrote a book on nuclear isomerism. The book was unfortunately not published because of the untimely death of Kurcharov and Rusinov in 1960. In 1961, Varshalovich was transferred to the Department of Theoretical Physics at LPTI, where he continued working in nuclear spectroscopy and interferential methods of studying gamma-ray emission of nuclei and at the same time became engaged in astrophysics. In 1963, he joined the Sector of theoretical research in astrophysics (now the Sector of theoretical astrophysics) just then founded on the initiative of the LPTI director B P Konstantinov (the first head of the Sector was A Z Dolginov). Varshalovich worked in this Sector for all of his life. In December of 1966, he defended his candidate (PhD) thesis ``Dynamic orientation of atoms in the cosmic medium.'' The paper appeared to be so significant that the official opponents Ya B Zel'dovich and I S Shklovskii, as well as Ya A Smorodinskii, who took part in the work of the committee, suggested that Varshalovich be given the degree of Doctor of Science in physics and mathematics. The chair of the dissertation committee, Konstantinov, and the members of the committee unanimously supported the suggestion (the decision of the committee was approved by the Higher Attestation Commission in May of 1968). From 1986 to 2010, Varshalovich was head of the Sector of theoretical astrophysics and managed to maintain the activity and operability of the Sector even in the period of deep crisis in the 1990s. Varshalovich had profound fundamental knowledge, great keenness and competence, scientific intuition, and the ability to put forward and implement original ideas. He made an invaluable contribution to the development of a number of areas in astrophysics. In the 1960s±1970s, he published a series of studies for the first time exploring the dynamic alignment of atomic and molecular spins in a rarefied cosmic medium caused by resonance scattering of anisotropic radiation fluxes. The effect proved to be important for the investigation of the physical parameters and chemical composition of interstellar gas clouds, the shells of stars, nebulae, comets, and other objects. At the same time, in the early 1960s, Varshalovich proposed the hypothesis (published in 1966) that maser pumping mechanisms in quantum transitions in hydrogen atoms can be realized in thermodynamically nonequilibrium interstellar gas clouds. The discovery in 1965 by radio astronomers of interstellar masers on transitions between rotational levels of OH molecules piqued his interest in cosmic masers. Uspekhi Fizicheskikh Nauk 190 (7) 783 ± 784 (2020) Translated by M V Tsaplina PERSONALIA PACS number: 01.60.+q

OH megamasers having very high luminosities in the spectral line can be effectively used for the probing of the evolutionary properties of the galaxies in the earliest cosmological epochs. The frequency shift of the emission line uniqually determines the redshift z , which tells about the epoch of emission. One of the important cosmological problems is the investigation of the galaxy mass spectrum in the expanding Universe. There is the empirical relation between the OH and far-infrared luminosities of galaxies. Therefore, if in the earliest cosmological epochs, there were galaxies with sufficient powerful infrared excesses and containing molecular material, they can be detected using the observations of their OH maser emission. The interacting and merging galaxies can be considered as the best candidates for such objects.

Recent observations (Matsumoto et al., 1988) indicate that at submillimeter wavelengths the spectrum of the cosmic background radiation (CBR) deviates from that of Planckian blackbody with a temperature T0R = 2.76 K. The relative excess of the flux ζ(v) = [F(v) – F0(v)] / F0(v) (where F(v) and F0(v) are the registered flux and the flux of the blackbody radiation at the frequency of the observations) are 0.6 at a frequency v1 = 380 GHz (λ = 709 μm) and 3.4 at a frequency v2 = 624 GHz (λ = 481 μm).

This paper is a brief review of molecular spectroscopy methods for the diagnostics of star-forming regions. Principal attention is paid to the determination of the kinetic temperature and gas density in dense clouds, the radiation field temperature, the magnetic field, and the spatial and velocity structure of regions of star formation.

Observations of the distribution of neutral hydrogen around the supernova remnants G 5.3 - 1.1 and G 24.7 + 0.6 made with the radio telescope RATAN-600 with resolution 2' x 130' x 6.3 kmsec have shown that these shells are surrounded by expanding H I shells of diameter 68 and 128 pc with masses 640 and 4.6 x 10/sup 3/ M/sub sun. The most probable mechanism of their formation is the outflow of a stellar wind during the lifetime of the stars on the main sequence. The masses of the stars have been estimated (17 and 38 M//sub sun/), and also the mass of the gas ejected in the supernova explosions

Observations of neutral hydrogen at wavelength 21 cm in the neighborhood of the supernova remnant W 50, which contains the unique object SS 433, have been made with the RATAN-600 radio telescope with resolution 2' x 130' x 6.3 km/sec. At a radial velocity of about 34 km/sec (kinematic distance 3 kpc) a patchy HI cloud is found with outer diameter 65 pc and mass approx. 3 x 10/sup 4/ M/sub circle/. In addition, at radial velocity 69 km/sec (kinematic distances 5.0 or 10.7 kpc) there is a HI cloud without appreciable large-scale motions. Some models that could explain the connection between these objects and the observed HI clouds are considered.