282 research outputs found

    Fluctuations of the intergalactic ionization field at redshift z ~ 2

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    (Abridged) Aims. To probe the spectral energy distribution (SED) of the ionizing background radiation at z ~ 2 and to specify the sources contributing to the intergalactic radiation field. Methods. The spectrum of a bright quasar HS1103+6416 (zem = 2.19) contains five successive metal-line absorption systems at zabs = 1.1923, 1.7193, 1.8873, 1.8916, and 1.9410. The systems are optically thin and reveal multiple lines of different metal ions with the ionization potentials lying in the extreme ultraviolet (EUV) range (1 Ryd to 0.2 keV). For each system, the EUV SED of the underlying ionization field is reconstructed by means of a special technique developed for solving the inverse problem in spectroscopy. For the zabs = 1.8916 system, the analysis also involves the HeI resonance lines of the Lyman series and the HeI 504 A continuum, which are seen for the first time in any cosmic object except the Sun. Results. From one system to another, the SED of the ionizing continuum changes significantly, indicating that the intergalactic ionization field at z ~ 2 fluctuates at the scale of at least Delta_z ~ 0.004. This is consistent with Delta_z ~ 0.01 estimated from HeII and HI Lyman-alpha forest measurements between the redshifts 2 and 3.Comment: 29 pages, 18 figures, 3 tables, accepted for publication in A\&

    Argon and Silicon abundances in the damped Ly-alpha system I Zw 18

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    We show that the difference between the Ar and Si relative abundance ratio derived from FUSE absorption spectra and from the HII regions of I Zw 18 is a consequence of the microturbulent analysis applied to the absorption spectra. FUSE observations were performed with a large entrance aperture which fully covered the galaxy. This means that the observed profiles are averaged over the full body of I Zw 18, implying that large-scale velocity fields influence the absorption - line profiles. Taking this into account, we show that the absorption spectra are consistent with the same metal abundances as those derived from the HII regions. It follows that no significant ionization correction as suggested by Izotov and collaborators to describe metal contents in damped Ly-alpha systems (DLA) is required to model abundances in the neutral gas of I Zw 18 (a local DLA system). Using a mesoturbulent approach and applying the generalized radiative transfer equation to the ArI1048 and SiII1020 lines observed by Vidal-Madjar et al., we found that the profiles may be reproduced with log (Ar/Si) ~= - 0.8 and N(SiII) ~= 4 10^{15} cm^{-2}.Comment: 4 pages, 2 eps figure, submitted to A

    The broad OVI absorber at z = 3.02 toward CTQ 325

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    We report on the multiphase absorption-line system detected at a redshift z = 3.021 in the spectrum of the quasi-stellar object CTQ 325 (z_em = 3.212). The system is displaced by ~14,000 km/s to the blue of the systemic velocity defined by the center of the symmetric OI quasar emission line. It consists of shallow and broad (~700 km/s, FWHM) absorption lines of HI 1215, CIV 1548,1550, and OVI 1032,1038, produced by collisionally ionized gas and of narrow absorption lines (FWHM < 20 km/s) of Ly-alpha, Ly-beta, ..., Ly-6, SiIII 1206, and CIII 977 produced by photoionized gas. Possible origins of this system are discussed.Comment: 6 pages, 4 figures, to appear in A&

    Measurability of kinetic temperature from metal absorption-line spectra formed in chaotic media

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    We present a new method for recovering the kinetic temperature of the intervening diffuse gas to an accuracy of 10%. The method is based on the comparison of unsaturated absorption-line profiles of two species with different atomic weights. The species are assumed to have the same temperature and bulk motion within the absorbing region. The computational technique involves the Fourier transform of the absorption profiles and the consequent Entropy-Regularized chi^2-Minimization [ERM] to estimate the model parameters. The procedure is tested using synthetic spectra of CII, SiII and FeII ions. The comparison with the standard Voigt fitting analysis is performed and it is shown that the Voigt deconvolution of the complex absorption-line profiles may result in estimated temperatures which are not physical. We also successfully analyze Keck telescope spectra of CII1334 and SiII1260 lines observed at the redshift z = 3.572 toward the quasar Q1937--1009 by Tytler {\it et al.}.Comment: 25 pages, 6 Postscript figures, aaspp4.sty file, submit. Ap

    Functioning of the Complex Metaphor “Politics is Animal World” in contemporary Mass-Media

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    Agafonova, O. I. Functioning of the Complex Metaphor “Politics is Animal World” in contemporary Mass-Media / O. I. Agafonova, M. S. Belozerova, S. Larini // Научный результат. Сер. Вопросы теоретической и прикладной лингвистики. - 2020. - Т.6, №1.-С. 3-11. - Doi: 10.18413/2313-8912-2020-6-1-0-1.The present article aims at the political discourse functioning as the medium for complex animal metaphor «POLITICS IS ANIMAL WORLD». The study of the animal metaphor in based on the material taken from the British and American web- based media. The metaphorical model is examined in the context of a discourse approach due to the intense interest to a man's mental world in the modern er

    Research into the specific aspects of internal conflict displays in the course of professional identification

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    The applicability of the researched issue is preconditioned by the need for detecting key determinants which define the process of the person's professional development, identification with the professional environment, and sources of professional self-efficacy. The purpose of the article is to provide the deliverables of the empiric research for the purpose of detection of an aggregate of professional values, internal conflicts therein and specific aspects of their displays in the course of professional establishment. The leading approach to the research has been an ascertaining experiment by means of standardised tools as well as approbation of the modified diagnostic technique which enables detecting essential aspects of internal conflicts and dynamics of their displays. The dynamic structure of professional values is analysed, and contents of the internal conflict and development thereof in the process of professional identity establishment are studied in the article. The article may be of use when developing processes of training and adaptation of young professions, determining professional reference points of production trainers and tutors in the course of vocational training. © 2016 Rensh, Kosyakova and Agafonova
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