Bibcode
DOI
Buitrago, J.; Goicoechea, L. J.
Referencia bibliográfica
Astrophysical Journal v.483, p.541
Advertised on:
7
1997
Número de citas
3
Número de citas referidas
3
Descripción
In an Omega 0 = 1 universe, within the classical Eulerian theory of
gravitational instability, the redshift evolution of a peculiar velocity
field in a region with arbitrary initial density contrast is derived,
for the first time, in real space and third-order perturbation theory. A
vector proportional to the gravitational acceleration can also be
expanded in terms of the redshift and the initial density contrast. The
results are applied to isolated (spherically symmetric) superclusters
and voids. Using reasonable models and the exact solution, we tested the
accuracy of three (linear, second order, and third order) approaches. A
numerical example showed that the relative error of the third-order
solutions (average density contrast and peculiar velocity) is less than
5% when 0 < delta <~ 1. In another example, a relative error was
derived (at -1 < delta < 0) of less than 10% (average density
contrast) to 2% (peculiar velocity). On the other hand, second-order
environmental dynamical terms (supercluster-supercluster,
supercluster-void, and void-void complexes) have been also obtained. In
the complexes (which contain two large-scale structures with spherical
symmetry at recombination), the global peculiar flow can be described as
a natural (but not trivial) superposition of two effective peculiar
flows. Given a member of a complex, its effective peculiar velocity
field is the sum of a spherically symmetric radial field (which is equal
to the peculiar velocity field obtained from an isolated evolution) and
an environmental (due to the interaction with the companion) field. In
general, the external tides can be comparable to the internal ones. The
imprint of the environment fields in the mean radial effective peculiar
flows is also studied.