Hunting down the acoustic scale after the cosmic high noon

Francisco Prada
(UAM/CSIC Madrid)


The discovery of cosmic acceleration has motivated the development of large experiments that aim to measure the expansion history of the universe and growth of structure with high precision at the 0.1-1% level. Ongoing and future galaxy, QSO and Ly-alpha surveys rely on the Baryon Acoustic Oscillation (BAO) technique which has undergone an enormous progress since the BAO feature was detected for the first time in the SDSS-II and 2dFGRS galaxy clustering. With the completion of BOSS in 2014, the current results for the galaxy survey predicts an improvement of 1% precision, which will be superseded by new experiments such as DESI and Euclid. Both surveys aim to measure the BAO scale to the sub-percent level over a wide redshift range 0.5 < z < 3.5, thus, providing unprecedented constraints on the dark energy equation of state. The new generation dark energy experiments also impose severe challenges on understanding any possible systematic shifts in the BAO signature due to nonlinear gravitational growth and scale-dependent bias to a high precision better than the measured statistical uncertainties. I'll present the new suite of BigMultiDark Planck simulations with large volume and high enough resolution to resolve the distinct and subhalo dark matter halo population that host typical BOSS galaxies. This allows for the first time to have a precise measurement of the halo BAO shifts and damping, and scale-dependent bias; which result very relevant for the interpretation of current and future galaxy surveys.