PCCP fellows meeting: A measure of dark energy with galaxy pairs.

par Christian Marinoni (Center of Theoretical Physics of Marseille)

vendredi 21 janv. 2011, 16:30 → 17:30 Europe/Paris

1222-RC-08 (LPNHE)

Thirty years ago, in a seminal letter published by Nature, Alcock &
Paczynski (AP) proposed a strategy to solve one of the most
outstanding issues of cosmology: measuring the curvature of the
universe with a model independent, purely geometrical,
approach. Despite its power and elegance, this idea has never been
substantiated.

Previous attempts to detect the AP effect failed because the peculiar,
non-Hubble, motions of cosmic objects induce AP-like distortions which
are difficult to model and subtract.  I will discuss how this issue
can be successfully addressed by studying the symmetry properties of
distant pairs of galaxies. Specifically, I will show that the pairs
orientation is a new and promising observable which can be used to
probe the value of fundamental cosmological parameters. I will present
the constraints obtained by implementing this method to archival data
from the SDSS and DEEP2 redshift surveys and speculate on the
precision achievable with data from future redshift surveys . I will
conclude by showing how the formalisms can be applied, on larger
cosmological scales, to assess the coherence of the Copernican
Principle.