Kinematic corrections to the averaged luminosity distance in inhomogeneous universes
(2009)cite arxiv:0910.2611
Comment: 32 pages, 30 figures added references, clarified the introduction.Abstract
The redshift surfaces within inhomogeneous universes are shifted by the
matter peculiar velocities. The arising average corrections to the luminosity
distance are calculated relativistically in several Swiss-cheese models with
mass compensated Lemaitre-Tolman-Bondi voids. These kinematic corrections are
different from weak lensing effects and can be much bigger close to the
observer. The statistical averaging over all directions is performed by tracing
numerically light rays propagating through a random void lattice. The
probability of a supernova emision from a comoving volume is assumed
proportional to the rest mass in it. The average corrections to the distance
modulus can be significant for redshifts smaller than 0.02 for small voids
(radius 30 Mpc) and redshifts smaller than 0.1 for big voids (radius 300 Mpc),
yet not large enough to substitute for dark energy. The corrections decay
inversely proportional to the distance from the observer. In addition, there is
a random cancelation of corrections between different voids which is more
severe in the model than in the real universe since the Swiss-cheese models are
not able to keep the void positions correlated close to the observer. Bigger
corrections can be achieved in models with larger peculiar velocities ($v>2000$
km/s) which could be due to either a significantly nonlinear regime today (high
density contrasts) or the presence of a decaying density perturbation mode. The
results obtained are qualitatively generic. They depend on the typical behavior
of the peculiar velocity field in voids, not on the chosen way to model the
inhomogeneities.
Description
[0910.2611] Kinematic corrections to the averaged luminosity distance in inhomogeneous universes