Issue |
A&A
Volume 366, Number 2, February I 2001
|
|
---|---|---|
Page(s) | 395 - 406 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361:20000103 | |
Published online | 15 February 2001 |
Classification of multifluid CP world models
Astronomisches Institut der Ruhr-Universität, 44780 Bochum, Germany e-mail: jthomas, hschulz@astro.ruhr-uni-bochum.de
H. Schulz
Received:
25
August
2000
Accepted:
14
November
2000
Various classification schemes exist for homogeneous and isotropic (CP) world models,
which include pressureless matter (so-called dust) and Einstein's cosmological
constant Λ. We here classify the solutions of more general world models
consisting of up to four non-interacting fluids, each with pressure ,
energy density
and an equation of state
with
.
In addition to repulsive fluids with negative pressure and positive energy density, which
generalize the classical repulsive (positive) Λ component, we
consider fluids with negative energy density as well. The latter generalize a negative
Λ component. This renders possible new types of models that do
not occur among the classical classifications of world models. Singularity-free periodic solutions as well as
further "hill-type", "hollow-type"and "shifting-type"models are feasible.
However, if one only allows for three components (dust, radiation and one repulsive component)
in a spatially flat universe
the repulsive classical Λ fluid (with
) tends to yield the smoothest
fits of the Supernova Ia data from
Perlmutter et al. (1999). Adopting the SN Ia constraints, exotic negative
energy density components can be fittingly included only if the universe consists of four or more fluids.
Key words: Cosmology: miscellaneous / Cosmology: theory
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.