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Dynamical interpretation of the Hubble sequence of galaxies

Abstract

Brosche (1970) has proposed a theory in which the energy loss due to collisions among gas clouds contained in a galaxy constitutes the driving mechanism for its evolution, through virial equilibrium states, which, from an initial spherical shape, makes it to contract towards an elongated form; moreover, the value of the total angular momentum, assumed as given by uniform rotation, is assumed to determine the galaxy type on the Hubble sequence and to influence strongly the contraction time from the initial spherical to the final flat configuration. The authors modify Brosche's scheme by assuming as models the rotating polytropes of Chandrasekhar and Lebovitz with variable density from centre to border. As a consequence of this change, centrifugal shedding of matter is attained at the equator of the contracting ellipsoid for a configuration with an axial ratio different from zero, so that, hereafter, a flat disk is formed surrounding the internal bulge, with a decreasing overall eccentricity; the rotation curve assumes then an aspect qualitatively similar to the one observed for spiral galaxies. The feedback of star formation which, by exhausting the material of the gas clouds, is able to stop the driving mechanism of evolution before the final flat stage  More>>
Authors:
Dallaporta, N; Secco, L [1] 
  1. Padua Univ. (Italy). Istituto di Astronomia
Publication Date:
Aug 01, 1977
Product Type:
Journal Article
Reference Number:
AIX-08-345302; EDB-78-047281
Resource Relation:
Journal Name: Astrophys. Space Sci.; (Netherlands); Journal Volume: 50:2
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALACTIC EVOLUTION; ANGULAR MOMENTUM; ANGULAR VELOCITY; COLLISIONS; COSMIC GASES; DIFFERENTIAL EQUATIONS; ENERGY LOSSES; GALAXIES; HUBBLE EFFECT; KINETIC ENERGY; ROTATION; SHAPE; STAR MODELS; CONFIGURATION; ENERGY; EQUATIONS; FLUIDS; GASES; MATHEMATICAL MODELS; MOTION; VELOCITY; 640105* - Astrophysics & Cosmology- Galaxies
OSTI ID:
5300300
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: APSSB
Submitting Site:
INIS
Size:
Pages: 253-279
Announcement Date:

Citation Formats

Dallaporta, N, and Secco, L. Dynamical interpretation of the Hubble sequence of galaxies. Netherlands: N. p., 1977. Web. doi:10.1007/BF00641737.
Dallaporta, N, & Secco, L. Dynamical interpretation of the Hubble sequence of galaxies. Netherlands. doi:10.1007/BF00641737.
Dallaporta, N, and Secco, L. 1977. "Dynamical interpretation of the Hubble sequence of galaxies." Netherlands. doi:10.1007/BF00641737. https://www.osti.gov/servlets/purl/10.1007/BF00641737.
@misc{etde_5300300,
title = {Dynamical interpretation of the Hubble sequence of galaxies}
author = {Dallaporta, N, and Secco, L}
abstractNote = {Brosche (1970) has proposed a theory in which the energy loss due to collisions among gas clouds contained in a galaxy constitutes the driving mechanism for its evolution, through virial equilibrium states, which, from an initial spherical shape, makes it to contract towards an elongated form; moreover, the value of the total angular momentum, assumed as given by uniform rotation, is assumed to determine the galaxy type on the Hubble sequence and to influence strongly the contraction time from the initial spherical to the final flat configuration. The authors modify Brosche's scheme by assuming as models the rotating polytropes of Chandrasekhar and Lebovitz with variable density from centre to border. As a consequence of this change, centrifugal shedding of matter is attained at the equator of the contracting ellipsoid for a configuration with an axial ratio different from zero, so that, hereafter, a flat disk is formed surrounding the internal bulge, with a decreasing overall eccentricity; the rotation curve assumes then an aspect qualitatively similar to the one observed for spiral galaxies. The feedback of star formation which, by exhausting the material of the gas clouds, is able to stop the driving mechanism of evolution before the final flat stage is attained has also been considered at several positions according to the value of the angular momentum. Numerical calculations seem to indicate that one can obtain in this way, by varying the angular momentum and the initial number of clouds, different galaxy types (elliptical, lenticular, spiral) resembling those of the Hubble sequence.}
doi = {10.1007/BF00641737}
journal = {Astrophys. Space Sci.; (Netherlands)}
volume = {50:2}
journal type = {AC}
place = {Netherlands}
year = {1977}
month = {Aug}
}