The turbulence spectrum of the interstellar plasma toward the pulsars PSR B0809+74 and B0950+08

The interstellar scintillation of the pulsars PSR B0809+74 and B0950+08 have been studied using observations at low radio frequencies (41, 62, 89, and 112 MHz), and the characteristic temporal and frequency scales for diffractive scintillations at these frequencies determined. A comprehensive analysis of the frequency and temporal structure functions reduced to a single frequency shows that the spectra of the inhomogeneities of the interstellar plasma toward both pulsars are described by a power law. The index of the interstellar plasma fluctuation spectrum toward PSR B0950+08 (n = 3.00 ± 0.05) differs appreciably from the Kolmogorov index. The spectrum toward PSR B0809+74 is a power law with index n = 3.7 ± 0.1. Strong angular refraction has been detected toward PSR B0950+08. Analysis of the distribution of inhomogeneities along the line of sight indicates that the scintillations of PSR B0950+08 take place in a turbulent layer with an enhanced electron density localized approximately 10 pc from the observer. The distribution of inhomogeneities for PSR B0809+74 is quasi-uniform. The mean square fluctuations of the electron density are estimated for inhomogeneities with characteristic scale ρ ₀ = 10⁷ m along the directions toward four pulsars. The local turbulence in the 10-pc layer is a factor of 20 higher on this scale than in the extended region responsible for the scintillations of PSR B0809+74.     

The lithological–geochemical characteristics for the Permian oil-and-gas bearing complex of the Lena-Anabar trough (based on the example of Ust’-Olenekskaya well no. 2370)

Lithofacies of different geneses are identified in a section of Permian deposits based on the study of the core material; the best reservoirs in the Permian complex of the Lena-Anabar trough are related to the sand bodies of the delta system. The Permian oil-source strata, where organic matter was accumulated under marine conditions, are recognized, the initial characteristics of organic matter are estimated, and the initial high oil-generation potential is substantiated. The results of the lithological–geochemical studies of the samples from one of the northernmost wells in the Laptev Sea coast have been published for the first time.     

Intensification of Biological Afterpurification of Municipal Wastewater by Some Pleistophyte Species

The use of semiaquatic plants (Pistia stratiotes and frogbit) for afterpurification of domestic wastewater is shown to improve water quality. Planting pleistophytes in watercourses and biological ponds, into which pretreated wastewater is discharged, is especially efficient in summer and autumn, when the load on treatment facilities increases.     

Geochemical features and sources of clastic material in Paleozoic terrigenous deposits of the northeastern flank of the South Mongolia–Khingan orogenic belt

The results of geological and geochemical studies of terrigenous rocks of the main stratigraphic subdivisions in the northeastern flank of the South Mongolia–Khingan orogenic belt and also the results of U-Pb (LА-ICP-MS) geochronological studies of detrital zircons from these deposits are presented. It is demonstrated that the studied rocks differ significantly in the nature of distribution of detrital zircon ages and, consequently, they cannot be members of a single sedimentary sequence. The data obtained confirm the standpoint according to which the northeastern flank of the South Mongolia–Khingan orogenic belt represents a “joint” zone separating the Argun and the Bureya-Jiamusi Superterranes. This joint zone was formed as the result of closure of the oceanic basin separating the specified continental massifs in the Paleozoic era. The geochemical features of the studied rocks indicate their formation in the conditions of the island arc or the active continental margin. Lack of zircon generations younger than Ordovician age in the studied samples allows assuming that the sedimentary sequences identified within the northeastern flank of the studied belt as the Necla, Dagmara, siltstone-sandstone, and Gramatukha sequences that formed from the end of the Vendian (?) to the Devonian correspond to the youngest stages of belt formation. These sediments in the current structural plan evidently represent fragments of accretion complexes cropping out in fragments among the Cenozoic sequences of the Amur-Zeya Depression.     

Simulation of Subterahertz Emission from the April 2, 2017 Solar Flare Based on the Multiwavelength Observations

Geomagnetism and Aeronomy - Millimeter (93 and 140 GHz) emission of the М6.4 solar flare detected on April 2, 2017 in the NOAA 12644 active region by the RT-7.5 telescope of the Bauman Moscow...     

On the Source of Sub-Terahertz Radiation of the Solar Flare on April 2, 2017

Geomagnetism and Aeronomy - The study analyzes the millimeter emission of a solar flare on April 2, 2017, observed by the Bauman Moscow State Technical University telescope RT-7.5. Based on the...     

RadioAstron Science Program Five Years after Launch: Main Science Results

The RadioAstron ground-space interferometer provides the highest angular resolution achieved now in astronomy. The detection of interferometric fringes from quasars with this angular resolution on baselines of 100–200 thousand km suggests the brightness temperatures which exceed the Compton limit by two orders of magnitude. Polarimetric measurements on ground-space baselines have revealed fine structure testifying to recollimation shocks on scales of 100–250 μas and a helical magnetic field near the base of radio emission in BL Lacertae. Substructure within a the scattering disk of pulsar emission on interferometer baselines (from 60000 to 250000 km) was discovered. This substructure is produced by action of the interstellar interferometer with an effective baseline of about 1 AU and the effective angular resolution of better than 1 μas. Diameters of scattering disks were measured for several pulsars, and distances to diffusing screens were evaluated. The ground-space observations of sources of the maser radiation in lines of water and hydroxyl have shown that the maser sources in star-forming regions remain unresolved on baselines, which considerably exceed the Earth diameter. These very compact and bright features with angular sizes of about 20–60 μas correspond to linear sizes of about 5–10 million km (several solar diameters).     

Observations and Interpretation of Rotational Properties of Polar Coronal Holes Based on SDO Data

Geomagnetism and Aeronomy - The rotational effect observed in variations of areas of polar coronal holes with a period of 14 days is analyzed with SDO data by using Coronal Hole Identification with...