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Can elliptical galaxies be equilibrium systems

Journal Article:

Abstract

This paper deals with the question of whether elliptical galaxies can be considered as equilibrium systems (i.e., the gravitational + centrifugal potential is constant on the external surface). We find that equilibrium models such as Emden-Chandrasekhar polytropes and Roche polytropes with n = 0 can account for the main part of observations relative to the ratio of maximum rotational velocity to central velocity dispersion in elliptical systems. More complex models involving, for example, massive halos could lead to a more complete agreement. Models that are a good fit to the observed data are characterized by an inner component (where most of the mass is concentrated) and a low-density outer component. A comparison is performed between some theoretical density distributions and the density distribution observed by Young et al. (1978) in NGC 4473, but a number of limitations must be adopted. Alternative models, such as triaxial oblate non-equilibrium configurations with coaxial shells, involve a number of problems which are briefly discussed. We conclude that spheroidal oblate models describing elliptical galaxies cannot be ruled out until new analyses relative to more refined theoretical equilibrium models (involving, for example, massive halos) and more detailed observations are performed.
Authors:
Caimmi, R [1] 
  1. Padua Univ. (Italy). Ist. di Astronomia
Publication Date:
Aug 01, 1980
Product Type:
Journal Article
Reference Number:
AIX-11-561019; EDB-81-101279
Resource Relation:
Journal Name: Astrophys. Space Sci.; (Netherlands); Journal Volume: 71:1
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXIES; STABILITY; CONFIGURATION; COSMOLOGICAL MODELS; DENSITY; EQUILIBRIUM; MATHEMATICAL MODELS; PHYSICAL PROPERTIES; 640105* - Astrophysics & Cosmology- Galaxies
OSTI ID:
6407889
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: APSSB
Submitting Site:
INIS
Size:
Pages: 75-85
Announcement Date:

Journal Article:

Citation Formats

Caimmi, R. Can elliptical galaxies be equilibrium systems. Netherlands: N. p., 1980. Web. doi:10.1007/BF00646909.
Caimmi, R. Can elliptical galaxies be equilibrium systems. Netherlands. doi:10.1007/BF00646909.
Caimmi, R. 1980. "Can elliptical galaxies be equilibrium systems." Netherlands. doi:10.1007/BF00646909. https://www.osti.gov/servlets/purl/10.1007/BF00646909.
@misc{etde_6407889,
title = {Can elliptical galaxies be equilibrium systems}
author = {Caimmi, R}
abstractNote = {This paper deals with the question of whether elliptical galaxies can be considered as equilibrium systems (i.e., the gravitational + centrifugal potential is constant on the external surface). We find that equilibrium models such as Emden-Chandrasekhar polytropes and Roche polytropes with n = 0 can account for the main part of observations relative to the ratio of maximum rotational velocity to central velocity dispersion in elliptical systems. More complex models involving, for example, massive halos could lead to a more complete agreement. Models that are a good fit to the observed data are characterized by an inner component (where most of the mass is concentrated) and a low-density outer component. A comparison is performed between some theoretical density distributions and the density distribution observed by Young et al. (1978) in NGC 4473, but a number of limitations must be adopted. Alternative models, such as triaxial oblate non-equilibrium configurations with coaxial shells, involve a number of problems which are briefly discussed. We conclude that spheroidal oblate models describing elliptical galaxies cannot be ruled out until new analyses relative to more refined theoretical equilibrium models (involving, for example, massive halos) and more detailed observations are performed.}
doi = {10.1007/BF00646909}
journal = {Astrophys. Space Sci.; (Netherlands)}
volume = {71:1}
journal type = {AC}
place = {Netherlands}
year = {1980}
month = {Aug}
}