Constraining inflation with the galaxy power spectrum and bispectrum

16.03.2018 11:30 – 12:30

In this seminar, I'd like to introduce some of my previous work and current research interests by discussing how galaxy clustering observations from future galaxy surveys like Euclid may be able to constrain inflation by looking for primordial non-Gaussianity (PNG). Planck data currently gives the strongest constraints on PNG--so far none has been detected, and the simplest inflationary models are consistent with the data. However, upcoming galaxy surveys will be able to improve on the Planck constraints by looking at late-time effects of primordial non-Gaussianity in the clustering statistics of galaxies. This is typically the galaxy power spectrum (or 2-point correlation function), but in principle all higher N-point correlation functions, starting with the bispectrum (or 3-point correlation function), can similarly be used to jointly constrain cosmology, galaxy bias, and new physics beyond LCDM, like primordial non-Gaussianity. First, I will present a forecast for how well we can constrain PNG by measuring the scale-dependence of the halo bias in the galaxy power spectrum. Then, I will discuss some of the anticipated challenges of using the bispectrum as an observational probe, and consider whether the statistical information in the bispectrum might be more easily accessed via different estimators of galaxy clustering, like the position-dependent power spectrum, line correlation function, and modal estimator. (This talk will be based on https://arxiv.org/abs/1409.5440 and https://arxiv.org/abs/1705.04392.)

Lieu

Bâtiment: Ecole de Physique

Salle 234, 24 quai Ernest-Ansermet

entrée libre