Francisco Kitaura

Signatures of the primordial Universe from its emptiness

Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the CMB, the distribution of galaxies, and the Lyman alpha forest. We propose to measure BAOs from the troughs (minima) of the density field.

We estimate the troughs from the empty circumspheres centres constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of 1,000 detailed simulated void catalogues are remarkably well confirmed by observational data. To the generation of such catalogues we have used improved perturbation theory and bias schemes, including halo and stellar mass reconstruction considering nonlinear, nonlocal and stochastic bias components.

We use the largest recently publicly available sample of Luminous Red Galaxies from SDSS-III BOSS to unveil for the first time a >3 sigma BAO detection from voids in observations. I will discuss the potential of this technique to obtain improved measures of the BAO in future surveys such as eBOSS, DESI, JPAS, LSST, 4MOST, or EUCLID.