3,984 research outputs found

    Superbroad Component in Emission Lines of SS 433

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    We have detected new components in stationary emission lines of SS 433; these are the superbroad components that are low-contrast substrates with a width of 2000--2500 km s-1 in He I λ4922\lambda4922 and Hβ\beta and 4000--5000 km s-1 in He II λ4686\lambda4686. Based on 44 spectra taken during four years of observations from 2003 to 2007, we have found that these components in the He II and He I lines are eclipsed by the donor star; their behavior with precessional and orbital phases is regular and similar to the behavior of the optical brightness of SS 433. The same component in Hβ\beta shows neither eclipses nor precessional variability. We conclude that the superbroad components in the helium and hydrogen lines are different in origin. Electron scattering is shown to reproduce well the superbroad component of Hβ\beta at a gas temperature of 20--35 kK and an optical depth for Thomson scattering τ\tau \approx 0.25--0.35. The superbroad components of the helium lines are probably formed in the wind from the supercritical accretion disk. We have computed a wind model based on the concept of Shakura-Sunyaev supercritical disk accretion. The main patterns of the He II line profiles are well reproduced in this model: not only the appearance of the superbroad component but also the evolution of the central two-component part of the profile of this line during its eclipse by the donor star can be explained.Comment: 17 pages, 13 figures, 2 tables, published in Astronomy Letters, 2013, vol. 39, N 12, pp. 826 - 84

    Deformed Oscillator Algebras and Higher-Spin Gauge Interactions of Matter Fields in 2+1 Dimensions

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    We formulate a non-linear system of equations which describe higher-spin gauge interactions of massive matter fields in 2+1 dimensional space-time and explain some properties of the deformed oscillator algebra which underlies this formulation. In particular we show that the parameter of mass MM of matter fields is related to the deformation parameter in this algebra.Comment: LaTex, 12 pages, no figures; Invited talk at the International Seminar Supersymmetry and Quantum Field Theory dedicated to the memory of Dmitrij V. Volkov; Kharkov, January 1997; to appear in the proceeding

    Dynamical lattice instability versus spin liquid state in a frustrated spin chain system

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    The low-dimensional s=1/2 compound (NO)[Cu(NO3)3] has recently been suggested to follow the Nersesyan-Tsvelik model of coupled spin chains. Such a system shows unbound spinon excitations and a resonating valence bond ground state due spin frustration. Our Raman scattering study demonstrates phonon anomalies as well as the suppression of a broad magnetic scattering continuum for temperatures below a characteristic temperature, T<T*=100K. We interpret these effects as evidence for a dynamical interplay of spin and lattice degrees of freedom that might lead to a further transition into a dimerized or structurally distorted phase at lower temperatures.Comment: 5 pages, 6 figure

    Quantum reflection of antihydrogen from a liquid helium film

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    We study the quantum reflection of ultracold antihydrogen atoms bouncing on the surface of a liquid helium film. The Casimir-Polder potential and quantum reflection are calculated for different thicknesses of the film supported by different substrates. Antihydrogen can be protected from anni- hilation for as long as 1.3s on a bulk of liquid 4He, and 1.7s for liquid 3He. These large lifetimes open interesting perspectives for spectroscopic measurements of the free fall acceleration of antihydrogen. Variation of the scattering length with the thickness of a film of helium shows interferences which we interpret through a Liouville transformation of the quantum reflection problem

    Predicting phase transition pressure in solids: a semiclassical possibility

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    This is a short review of the physical ideas,algorithm for calculations and some results of a semiclassical theory of the behaviour of materials under high pressure,proposed by P.Savic and R.Kasanin.The theory has found applications from DAC experiments to studies of planetary interior structure.Comment: PDF file,no figure

    The Kola Peninsula: Geography, History and Resources

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    The Kola Peninsula in northwest Russia is one of the most important economic regions in the circumpolar North. The region contains valuable natural resources, including a wide variety of mineral and fish resources, and is proximate to the large gas fields of the Barents Sea. A large population, industrial complexes, and military infrastructure are also characteristic of the region. The Kola Peninsula developed rapidly during the Soviet period (1917-92) under the principles of socialist development policy. This policy favoured extensive resource extraction and industrialization and resulted in increased northern settlement, much of it involuntary. Soviet development policy prompted the opening of new mines and the construction of smelters and refining facilities, while Soviet military policy necessitated the establishment of large military basing operations. Resource development and processing have led to severe environmental damage in the region and beyond. This paper describes the geographical features of the Kola Peninsula and the region's development history and contains data on natural and labour resources.Key words: Kola Peninsula, Murmansk Region, Murmansk, Russian Arctic, Soviet Arctic, natural resources, economic development, militarizationLa presqu'&icirc;le de Kola dans le nord-ouest de la Russie est l'une des plus importantes zones &eacute;conomiques du Grand Nord circumpolaire. La r&eacute;gion contient de pr&eacute;cieuses ressources naturelles, y compris une grande vari&eacute;t&eacute; de ressources mini&egrave;res et de poisson, et elle est proche des champs gaziers de la mer de Barents. Cette r&eacute;gion se caract&eacute;rise aussi par une forte population, ainsi que par la pr&eacute;sence de complexes industriels et d'une infrastructure militaire. La presqu'&icirc;le de Kola s'est d&eacute;velopp&eacute;e rapidement au cours de l'&egrave;re sovi&eacute;tique (1917-1992), selon les principes des politiques socialistes de d&eacute;veloppement. Ces derni&egrave;res, qui mettaient l'accent sur une intensification de l'exploitation des ressources et de l'industrialisation, ont accru la colonisation - en grande partie forc&eacute;e - dans le Nord. Les politiques sovi&eacute;tiques de d&eacute;veloppement ont amen&eacute; l'ouverture de nouvelles mines et la construction de fours de fusion et de raffineries, tandis que les politiques militaires sovi&eacute;tiques ont rendu n&eacute;cessaire l'&eacute;dification d'importantes installations pour des bases militaires. L'exploitation et le traitement des ressources ont caus&eacute; dans la r&eacute;gion imm&eacute;diate et au-del&agrave; de s&eacute;rieux dommages &eacute;cologiques. Cet article d&eacute;crit les caract&eacute;ristiques g&eacute;ographiques de la presqu'&icirc;le de Kola et l'histoire du d&eacute;veloppement de la r&eacute;gion, et il pr&eacute;sente des donn&eacute;es sur les ressources naturelles et en main-d'oeuvre.Mots cl&eacute;s : presqu&rsquo;&icirc;le de Kola, r&eacute;gion de Mourmansk. Mourmansk, Arctique russe, Arctique sovibtique, ressources naturelles, d&eacute;veloppement &eacute;conomique, militarisatio

    Free totally (anti)symmetric massless fermionic fields in d-dimensional anti-de Sitter space

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    Free massless fermionic fields of arbitrary spins s>0s>0 corresponding to totally (anti)symmetric tensor-spinor representations of the SO(d1)SO(d-1) compact subgroup and in dd-dimensional anti-de Sitter space are investigated. We propose the free equations of motion, subsidiary conditions and corresponding gauge transformations for such fields. The equations obtained are used to derive the lowest energy values for the above-mentioned representations. A new representation for equations of motion and gauge transformations in terms of generators of anti-de Sitter group SO(d1,2)SO(d-1,2) is found. It is demonstrated that in contrast to the symmetric case the gauge parameter of the antisymmetric massless field is also a massless field.Comment: 9 pages, LaTe

    Lagrangian Formulation for Free Mixed-Symmetry Bosonic Gauge Fields in (A)dS(d)

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    Covariant Lagrangian formulation for free bosonic massless fields of arbitrary mixed-symmetry type in (A)dS(d) space-time is presented. The analysis is based on the frame-like formulation of higher-spin field dynamics [1] with higher-spin fields described as p-forms taking values in appropriate modules of the (A)dS(d). The problem of finding free field action is reduced to the analysis of an appropriate differential complex, with the derivation Q associated with the variation of the action. The constructed action exhibits additional gauge symmetries in the flat limit in agreement with the general structure of gauge symmetries for mixed-symmetry fields in Minkowski and (A)dS(d) spaces.Comment: 17 pages, v2: clarifications added, misprints corrected; v3: minor changes, typos correcte
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