• Outline of the unified theory...

Result: Outline of the unified theory of spiral and bar-like structures in galaxies

Title:
Outline of the unified theory of spiral and bar-like structures in galaxies
Authors:
POLYACHENKO, E. V
Source:
Monthly Notices of the Royal Astronomical Society. 348(1):345-354
Publisher Information:
Oxford: Blackwell Science, 2004.
Publication Year:
2004
Physical Description:
print, 30 ref
Original Material:
INIST-CNRS
Subject Terms:
Astronomy earth cosmic environment, Astronomie et environnement cosmique terrestre, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Astronomie, Astronomy, Systèmes stellaires. Objets et systèmes galactiques et extragalactiques. L'univers, Stellar systems. Galactic and extragalactic objects and systems. The universe, Caractéristiques et propriétés des galaxies externes et des objets extragalactiques, Characteristics and properties of external galaxies and extragalactic objects, Bras spiraux et barres. Disques galactiques, Spiral arms and bars. Galactic disks, Barre galactique, Galactic bar, Barra galáctica, Champ gravitationnel, Gravitational fields, Equation intégrale, Integral equations, Excitation, Mode propre, Eigenmode, Modo propio, Orbite, Orbits, Problème valeur propre, Eigenvalue problem, Problema valor propio, Précession, Precession, Résonance Lindblad, Lindblad resonance, Resonancia Lindblad, Solution numérique, Numerical solution, Structure galactique, Galactic structure, Structure spirale, Spiral structure, Estructura espiral, Théorie unifiée, Unified theory, Teoría unificada, Structure galaxies, Galaxy structure, Estructura galaxias
Document Type:
Academic journal Article
File Description:
text
Language:
English
Author Affiliations:
Institute of Astronomy, Moscow 119017, Russian Federation
ISSN:
0035-8711
Access URL:
http://pascal-francis.inist.fr/vibad/index.php?action=search&terms=15517617
Rights:
Copyright 2004 INIST-CNRS
CC BY 4.0
Sauf mention contraire ci-dessus, le contenu de cette notice bibliographique peut être utilisé dans le cadre d’une licence CC BY 4.0 Inist-CNRS / Unless otherwise stated above, the content of this bibliographic record may be used under a CC BY 4.0 licence by Inist-CNRS / A menos que se haya señalado antes, el contenido de este registro bibliográfico puede ser utilizado al amparo de una licencia CC BY 4.0 Inist-CNRS
Notes:
Astronomy
Accession Number:
edscal.15517617
Database:
PASCAL Archive

Further Information

This paper presents a new approach to studying galactic structures. They are considered as the low-frequency normal modes in a disc of orbits precessing at different angular speeds. Such a concept is an adequate alternative to the commonly used approach of treating the disc as a set of individual stars rotating at near-circular orbits around the centre. The problem of determining the normal modes is reduced to a simple integral equation in the form of the classical eigenvalue problem, where the eigenvalue is directly equal to the pattern speed of the mode, Ωp. An examination of the general properties of the basic integral equation shows that two types of solutions exist, bar-like and spiral. The numerical solutions of both types are obtained. The characteristic pattern speeds are of the order of the mean orbit precession speed, although for the bar modes Ωp can markedly exceed the maximum precessing speed of orbits. It is shown that the bar mode grows due to the immediate action of its gravitational field on the stars in the resonance regions. As for the spiral mode, its excitation is probably due to the inner Lindblad resonance, which can promote mode growth.