Improving the calculation of uncertainty on dark energy
Astronomy and astrophysics
Thursday 31 May 2012
to 15:00 at
Joachim Harnois-Deraps (University of Toronto)
I will be discussing various improvements on the uncertainty estimate about the dark energy equation of state, with a special focus on the technique of
baryonic acoustic oscillations (BAO).
Current analyses of wide galaxy surveys can detect an excess in the two-point function of the mass distribution,
which roots in sound waves that propagated in the primordial plasma. This excess occurs at a comoving scale of about 100 Mpc, and is well understood from a theoretical
point of view. A detection of this bump at different redshifts allows for a mapping of the expansion history of the Universe, which is in turn sensitive to the amount and
evolution of dark energy. In existing analyses however, the uncertainty estimates are mostly based on linear theory calculations, whereas the density field has undergone
non-linear gravitational collapse, thus biasing the results. I will start by reviewing the BAO approach to dark energy and the current treatment of the uncertainty,
and describe various improvements that were recently suggested.