Relation between parameters of dust and parameters of molecular and atomic gas in extragalactic star-forming regions

The relationships between atomic and molecular hydrogen and dust of various sizes in extragalactic star-forming regions are considered, based on observational data from the Spitzer and Herschel infrared space telescopes, the Very Large Array (atomic hydrogen emission) and IRAM (CO emission). The source sample consists of approximately 300 star-forming regions in 11 nearby galaxies. Aperture photometry has been applied to measure the fluxes in eight infrared bands (3.6, 4.5, 5.8, 8, 24, 70, 100, and 160$\mu$m), the atomic hydrogen (21cm) line and CO (2--1) lines. The parameters of the dust in the starforming regions were determined via synthetic-spectra fitting, such as the total dust mass, the fraction of polycyclic aromatic hydrocarbons (PAHs), etc. Comparison of the observed fluxes with the measured parameters shows that the relationships between atomic hydrogen, molecular hydrogen, and dust are different in low- and high-metallicity regions. Low-metallicity regions contain more atomic gas, but less molecular gas and dust, including PAHs. The mass of dust constitutes about $1\%$ of the mass of molecular gas in all regions considered. Fluxes produced by atomic and molecular gas do not correlate with the parameters of the stellar radiation, whereas the dust fluxes grow with increasing mean intensity of stellar radiation and the fraction of enhanced stellar radiation. The ratio of the fluxes at 8 and 24$\mu$m, which characterizes the PAH content, decreases with increasing intensity of the stellar radiation, possibly indicating evolutionary variations of the PAH content. The results confirm that the contribution of the 24$\mu$m emission to the total IR luminosity of extragalactic star-forming regions does not depend on the metallicity.Comment: Published in Astronomy Reports, 2017, vol. 61, issue

Extended ionized-gas structures in seyfert 2 galaxy Mrk 78

The search and study of extended emission-line regions (EELRs) related to AGN in early-type galaxies is interesting to probe the history of nuclear ionization activity and also to understand the process of external gas accretion. In this work, we present observations of the EELR in Mrk 78 obtained at the 6-m Russian telescope using the long-slit and 3D spectroscopy methods. We show that ionized-gas clouds at 12-16 kpc projected distances from the nucleus are ionized by the AGN radiation. Also we have checked if the galaxy appearing in the optical images in the immediate neighbourhood of Mrk 78 near the external clouds is a dwarf companion or a part of a tidal structure. However, the spectrum of this galaxy, SDSS J074240.37+651021.4, obtained at the 6-m telescope corresponds to a distant background galaxy with z = 0.38. © 2020, Astronomical Institute, Slovak Academy of Sciences.Russian Science Foundation, RSF: 17-12-01335Ministry of Science and Higher Education of the Russian FederationAcknowledgements. This study was supported by the Russian Science Foundation, project no. 17-12-01335 ‘Ionized gas in galaxy discs and beyond the optical radius’ and based on the observations conducted with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation. Authors are grateful to Victor Afanasiev for his interest to this work. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration

CEP-stable Tunable THz-Emission Originating from Laser-Waveform-Controlled Sub-Cycle Plasma-Electron Bursts

We study THz-emission from a plasma driven by an incommensurate-frequency two-colour laser field. A semi-classical transient electron current model is derived from a fully quantum-mechanical description of the emission process in terms of sub-cycle field-ionization followed by continuum-continuum electron transitions. For the experiment, a CEP-locked laser and a near-degenerate optical parametric amplifier are used to produce two-colour pulses that consist of the fundamental and its near-half frequency. By choosing two incommensurate frequencies, the frequency of the CEP-stable THz-emission can be continuously tuned into the mid-IR range. This measured frequency dependence of the THz-emission is found to be consistent with the semi-classical transient electron current model, similar to the Brunel mechanism of harmonic generation

Shell-model description of monopole shift in neutron-rich Cu

Variations in the nuclear mean-field, in neutron-rich nuclei, are investigated within the framework of the nuclear shell model. The change is identified to originate mainly from the monopole part of the effective two-body proton-neutron interaction. Applications for the low-lying states in odd-$A$ Cu nuclei are presented. We compare the results using both schematic and realistic forces. We also compare the monopole shifts with the results obtained from large-scale shell-model calculations, using the same realistic interaction, in order to study two-body correlations beyond the proton mean-field variations.Comment: Phys. Rev. C (in press

Theory of high-order harmonic generation from molecules by intense laser pulses

We show that high-order harmonics generated from molecules by intense laser pulses can be expressed as the product of a returning electron wave packet and the photo-recombination cross section (PRCS) where the electron wave packet can be obtained from simple strong-field approximation (SFA) or from a companion atomic target. Using these wave packets but replacing the PRCS obtained from SFA or from the atomic target by the accurate PRCS from molecules, the resulting HHG spectra are shown to agree well with the benchmark results from direct numerical solution of the time-dependent Schr\"odinger equation, for the case of H$_2^+$ in laser fields. The result illustrates that these powerful theoretical tools can be used for obtaining high-order harmonic spectra from molecules. More importantly, the results imply that the PRCS extracted from laser-induced HHG spectra can be used for time-resolved dynamic chemical imaging of transient molecules with temporal resolutions down to a few femtoseconds.Comment: 10 pages, 5 figure

Effect oF Ligand's Nature on Chemical Deposition by Sodium Sulphate of Sodium thin CdSe Films

The work was financially supported by program 211 of the Government of the Russian Federation (No. 02.A03.21.0006.

Model of the influence of the speed of communication and ambient temperature on the electric power consumption of an electric bus

The development of the electric bus fleet, observed in the world and, in particular, in the Russian Federation, leads to the emergence of new scientific and practical problems that need to be addressed. So, at present, when electric buses are put into operation, in practice, problems arise with the choice of a rational urban regular route and the organization of charging infrastructure on it. To solve this problem, you need to know the power consumption of an electric bus, which depends on the operating conditions. This article analyzes scientific research in the field of modeling electricity consumption by an electric bus. Such an analysis and study of the experience of operating an electric bus in Tyumen made it possible to single out the factors on which electricity consumption depends. In the course of the study, a hypothesis was formulated: the factors characterizing the operating conditions on the route can be taken into account by one indicator «speed of communication». At the same time, until now, no direct influence of the ambient temperature on the power consumption of an electric bus has been revealed. Therefore, the aim of the study is to study the effect of traffic speed and ambient temperature on the electricity consumption of an electric bus on a regular urban route. To achieve this goal, a passive experiment was carried out, during which data was obtained on the functioning of electric buses, the technical parameters of the charging stations and the ambient temperature. To test the hypothesis, the initial amount of experimental information was processed using statistical data processing methods. It was found that a decrease in the speed of communication causes an increase in the consumption of electricity by an electric bus. During the analysis of the influence of the ambient air temperature on the considered output parameter, it was revealed that when it deviates from the value equal to + 4 °C, an increase in the consumption of electricity by the electric bus is observed. As a result, the established regularities of the influence of the speed of communication and the ambient air temperature on the electricity consumption of an electric bus and their mathematical models will become the basis for further research for the development of a methodology for rationing electricity consumption by an electric bus on a regular city route