Baryon Acoustic Oscillation Scale Measurements from Galaxy Bispectrum

Baryon Acoustic Oscillation (BAO) signature plays a very important role in observational cosmology. It has been observed many times in the power spectrum of galaxy distributions in the past. The scale of the BAO can be used to derive robust measurements of the distance scale and put constraints on models of Dark Energy. One of the key steps in measuring the BAO scale is to make sure it is isolated in such a way that the resulting measurements are not contaminated from the broadband shape of the galaxy power spectrum, the later being more sensitive to the specifics of the galaxy formation and nonlinear effects.

The same BAO signal is also present in the bispectrum of galaxies. Recent works have attempted to measure this signal but the results are still behind in terms of robustness when compared to the standard, power spectrum based analysis. One important problem to overcome is to remove the contribution from the broadband bispectrum component in the same way we do for the power spectrum.

I will present our recent work that made significant progress in this direction. We derived templates for removing the broadband shape of the bispectrum from BAO measurements based on high quality N-body simulations. I will show how the results depend on the marginalization of over nuisance parameters and how much independent information BAO in the bispectrum adds to the standard analysis. I will also talk about ways of solving other problems associated with the galaxy bispectrum BAO analysis such as the difficulties in estimating the covariance matrices.