Issue |
A&A
Volume 464, Number 3, March IV 2007
|
|
---|---|---|
Page(s) | 811 - 814 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20066436 | |
Published online | 22 January 2007 |
A coarse-grained field theory for density fluctuations and correlation functions of galaxies and clusters
Astrophysics Center, University of Science and Technology of China, Hefei, Anhui, PR China e-mail: yzh@ustc.edu.cn
Received:
25
September
2006
Accepted:
21
November
2006
Aims.We aim to investigate the large-scale structure of the universe
from a field-theoretical perspective, and to give a unifying understanding of several seemingly unrelated observed features of clusterings of galaxies and clusters, such as the dependence of clustering amplitude on mass and luminosity,
the departure of the correlation function from the power law
,
the oscillatory behavior of
for clusters
on very large scales, and the scaling of r0 with the mean separation d of clusters.
Methods.We present a coarse-grained field theory of density fluctuations for a Newtonian self-gravitating many-body system, apply it to a homogeneous Universe with small density fluctuations, and uniformly treat the clustering of all types of galactic objects in terms of the field of density fluctuations.
Results.The Jeans length , a unique physical scale for a gravitating system,
appears naturally as the characteristic scale underlying the large-scale structure.
Under a Gaussian approximation the analytic expressions of
and
are obtained.
The correlation amplitude is proportional to the galactic
mass,
, and
departures from the power law
around
h-1 Mpc, and is oscillating over large scales ~100 h-1 Mpc
and damped to zero. The spectrum amplitude is inversely proportional
to the galactic number density,
,
and
in the range
h Mpc-1.
The scaling
holds quantitatively.
Conclusions.These preliminary analytic results under the Gaussian approximation already
qualitatively explain these pronounced
features of the observed large-scale structures. Yet on small
scales the predicted clustering is insufficient, and the peak of is too sharp. These deficiencies are due to neglecting
higher order nonlinear effects, which need to be studied further.
Key words: cosmology: large-scale structure of Universe / cosmology: theory / galaxies: clusters: general / gravitation / hydrodynamics / instabilities
© ESO, 2007
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