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During the last decades, ground-based microwave radiometry has matured into an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high-altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O, and O3, can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites; more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is urgent today as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented. The radiometer, its calibration scheme, and its observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuations at the two frequencies and error characterization, are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO (57[deg] N, 12[deg] E), is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The data sets from the instruments agree well with each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias of mesospheric winter values of CO from MLS compared to ground-based instruments was reported earlier.

The formation of first molecules, negative Hydrogen ions, and molecular ions in a model of the Universe with cosmological constant and cold dark matter is studied. The cosmological recombination is described in the framework of modified model of the effective 3-level atom, while the kinetics of chemical reactions is described in the framework of the minimal model for Hydrogen, Deuterium, and Helium. It is found that the uncertainties of molecular abundances caused by the inaccuracies of computation of cosmological recombination are approximately 2–3%. The uncertainties of values of cosmological parameters affect the abundances of molecules, negative Hydrogen ions, and molecular ions at the level of up to 2%. In the absence of cosmological reionization at redshift z = 10, the ratios of abundances to the Hydrogen one are 3.08 × 10 –13 for H – , 2.37 × 10 –6 for H 2 , 1.26 × 10 –13 for H 2 + , 1.12 × 10 –9 for HD, and 8.54 × 10 –14 for HeH + .

An analytical solution of the Kompaneets equation is found for a medium whose density varies according to a hyperbolic tangent law, from a more diffuse (interstellar) medium to a denser medium (a cloud). The law of motion of the leading points of the shock front is discussed. Intermediate asymptotics describing the acceleration and change of the shape of the shock front are analyzed in detail. The obtained solution can be used to investigate analytically the evolution of the shock-front shape at a boundary with a molecular cloud.

The high-mass star-forming region IRAS 17333-3606 has been mapped in the 13 CO ( J = 2–1) and C 18 O ( J = 2–1) lines in the submillimeter wavelength range using the APEX (Chile) radio telescope. The analysis of the low-velocity part of the molecular outflow has been carried out, and the main parameters of the outflow have been determined. We have used a novel approach for calculating parameters of the low-velocity part of bipolar molecular outflows in molecular clouds. The approach excludes the influence of the surrounding cloud on the parameters of the outflow. The mass of the low-velocity part is much greater than that of the high-velocity part of the molecular outflow, while their energies are comparable. The core of the young stellar object is significantly deformed by the impact of the bipolar outflow.

The paper aims at establishing relations between the parameters of methanol maser emission that originates in dense star-forming regions and parameters of a dense core using emission of the CS molecule. A total of 164 sources toward the positions of methanol masers using the RT-22 radio telescope at CrAO, Ukraine, have been observed. For 85 sources, the CS (J = 2–1) line emission was detected. Most of the sources have been selected from catalogs of the class I and class II methanol masers. For methanol masers, this is the most complete survey in the CS (J = 2–1) line on the northern sky. A comparative analysis of parameters of methanol masers spectra in the CS (J = 2–1) line, and methanol masers, luminosities of dense cores, and infrared sources, has been performed. The detection rates of the CS (J = 2–1) line emission, its intensities and widths, the differences between the systematic velocities and velocities of the maser line centers have been investigated. The radiation detection rates in the CS (J = 2–1) line are shown to differ for various source samplings. The form of the dependences lgLcs – lgLbol, lgLmas – lgLcs and lgLmas – lgLbol has been found for sources with which methanol masers are associated. Based on the luminosity of infrared sources, samples of sources in which the CS (J = 2–1) line emission is detected with a higher probability have been determined.

Five regions of massive-star formation have been observed in various molecular lines in the frequency range∼85−89 GHz. The studied regions comprise dense cores, which host young stellar objects. The physical parameters of the cores are estimated, including the kinetic temperatures (∼20−40 K), the sizes of the emitting regions (∼0.1−0.6 pc), and the virial masses (∼40−500 M ⊙ ). The column densities and abundances of various molecules are calculated assuming Local Thermodynamical Equilibrium(LTE). The core in 99.982+4.17, which is associated with the weakest IRAS source, is characterized by reduced molecular abundances. The molecular line widths decrease with increasing distance from the core centers ( b ). For b ≳ 0.1 pc, the dependences Δ V ( b ) are close to power laws (∝ b − p ), where p varies from ~0.2 to ~0.5, depending on the object. In four cores, the asymmetries of the optically thick HCN(1–0) and HCO + (1–0) lines indicates systematicmotions along the line of sight: collapse in two cores and expansion in two others. Approximate estimates of the accretion rates in the collapsing cores indicate that the forming stars have masses exceeding the solar mass.

New method for calculating parameters of low-velocity components of bipolar outflows in molecular clouds is presented. The method takes into account all possible bipolar flow effects on spectral lines: the line profile asymmetry, the presence of line wings, and the systematic shift of the line profile as a whole along the axis of the outflow. The method is adapted to calculating parameters of weak bipolar outflows and flows with low S/N ratios in their spectra. Using this method, the parameters of bipolar outflows in the source G122.0-7.1 are calculated.

During the last decades, ground-based microwave radiometry has matured into an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high-altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H.sub.2 O, and O.sub.3, can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites; more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is urgent today as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O.sub.3 at 110.84 GHz is presented. The radiometer, its calibration scheme, and its observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuations at the two frequencies and error characterization, are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO (57°â€¯N, 12°â€¯E), is analysed. The retrieved vertical profiles are compared with co-located CO and O.sub.3 data from the MLS instrument on the Aura satellite. The data sets from the instruments agree well with each other. The main differences are the higher OSO volume mixing ratios of O.sub.3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias of mesospheric winter values of CO from MLS compared to ground-based instruments was reported earlier.

An ultra-low-voltage crystal quartz oscillator is proposed. The approach to its design is essentially based on using a HEMT operating in unsaturated dc regime and a quartz resonator as a resonant impedance transformer. The 25 MHz prototype shows steady oscillations at the supply voltage of less than 17 mV and the power consumption as low as 300 nW, i.e., 1-2 orders of magnitude lower than other to-date oscillators. This approach is good for building ultra-low consumption radio devices including those working at low temperatures.

The interband time lags between the flux variations of the Q2237+0305 quasar have been determined from light curves in the Johnson-Cousins V, R, and I spectral bands. The values of the time lags for filter pairs R-V, I-R, and I-V are significantly higher than those predicted by the standard accretion disk model by Shakura and Sunyaev. To explain the discrepancy, the idea of a supercritical accretion regime in quasars considered in 1973 by Shakura and Sunyaev is applied. This regime has been shown by them to cause an extended scattering envelope around the accretion disk. The envelope efficiently scatters and re-emits the radiation from the accretion disk and thus increases the apparent disk size. We made use of analytical expressions for the envelope radius and temperature derived by Shakura and Sunyaev in their analysis of super-Eddington accretion and show that our results are consistent with the existence of such an envelope. The corresponding parameters of the accretion regime were calculated. They provide the radii of the envelope in the V, R, and I spectral bands consistent with the inter-band time lags determined in our work.