282 research outputs found
Fluctuations of the intergalactic ionization field at redshift z ~ 2
(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
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
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
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
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
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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