Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'487'895
Articles rated: 2609

28 March 2024
 
  » arxiv » astro-ph/9801115

 Article overview


Fractal Dimensions and Scaling Laws in the Interstellar Medium and Galaxy Distributions: a new Field Theory Approach
H. J. de Vega ; N. Sánchez ; F. Combes ;
Date 13 Dec 1997
Subject astro-ph cond-mat gr-qc hep-ph hep-th
AbstractWe develop a field theoretical approach to the cold interstellar medium (ISM) and large structure of the universe. We show that a non-relativistic self- gravitating gas in thermal equilibrium with variable number of atoms or fragments is exactly equivalent to a field theory of a scalar field phi(x) with exponential self-interaction. We analyze this field theory perturbatively and non-perturbatively through the renormalization group(RG).We show scaling behaviour (critical) for a continuous range of the physical parameters as the temperature. We derive in this framework the scaling relation M(R) sim R^{d_H} for the mass on a region of size R, and Delta v sim R^frac12(d_H -1) for the velocity dispersion. For the density-density correlations we find a power-law behaviour for large distances sim |r_1 - r_2|^{2D - 6}.The fractal dimension D turns to be related with the critical exponent u by D = 1/ u. Mean field theory yields u = 1/2, D = 2. Both the Ising and the mean field values are compatible with the present ISM observational data:1.4leq D leq 2. We develop a field theoretical approach to the galaxy distribution considering a gas of self-gravitating masses on the FRW background, in quasi-thermal equi- librium. We show that it exhibits scaling behaviour by RG methods. The galaxy correlations are computed without assuming homogeneity. We find < ho({vec r_0}) ho({vec r_0} + {vec r}) > sim r^{D-3} $. The theory allows to compute the three and higher density correlators without any assumption.We find that the connected N-points density scales as r_1^{N(D-3)}, when $ r_1 >> r_i, 2leq i leq N $. There are no free parameters in this theory.
Source arXiv, astro-ph/9801115
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica