Baryonic Acoustic Oscillations in Large-Scale Structures

The upcoming Dark Energy Spectroscopic Instrument (DESI) will measure the positions of numerous galaxies and measure the effect of dark energy on the expansion of the universe. By estimating the power spectrum monopole from the galaxy clustering in the Universe I can deduce information about the geometry of space-time. From the latter I will measure the baryon acoustic oscillations in the power spectrum of the galaxy clustering data of the DESI collaboration. This will allow me, by applying advanced statistical methods such as Monte Carlo Markov Chain models, to deduce constraints for cosmological parameters. Separating the measurement of the power spectrum in a component along the line of sight and perpendicular to it, I will be able to measure the Alcock-Paczynski test with both the redshift space distortion and baryon acoustic oscillations signals. The Alcock-Paczynski test describes a distortion in an otherwise isotropic feature in the galaxy clustering when the assumed fiducial cosmological model used to transfer the measured redshifts into distances deviates from the true cosmology. This anisotropic signal may appear degenerate with the redshift space distortion signal in a featureless power spectrum. Using the baryon acoustic oscillations signal, it will be possible to break this degeneracy and exploit all three signals, redshift space distortion, baryon acoustic oscillations and the Alcock-Paczynski effect for cosmological parameter constraints. Currently, I am working on an accurate and robust power spectrum estimator for simulated and real data. In the near future, we will subsequently add additional features to the model in order to extract the BAO signal.