TY - BOOK

T1 - Testing Cosmological Models

T2 - Will the real non-caussianity please stand up.

AU - Nielsen, Jeppe Trøst

PY - 2017

Y1 - 2017

N2 - The concordance model of cosmology is remarkable for its apparent simplicity, andvast range of predictions. Yet its two most well known and infamous ingredients,dark energy and inflation, have so far avoided all attempts at direct observation. Evenso, theorists invent ever more exotic models, and experiments must keep up at anever increasing pace, preserving both precision and accuracy in the analysis.In this thesis I compute corrections to large scale structure observables, correctionswe expect solely due to general relativity. The calculations can be perceived in twoways. The pessimist will say these effects are unwanted systematics in the search forprimordial physics, the optimist will see it as a chance to test general relativity toever increasing precision. Regardless, these effects must be computed as part of theinterpretation of coming observations.I calculate the predicted bispectrum in galaxy number counts from general relativisticeffects. This includes in particular lensing, which will systematically shift theobserved bispectrum for observations of large scale structure. Furthermore, I developand explore a scheme for fast computation of the galaxy number count spectra, inthe flat-sky approximation.The last part of the work is a numerical analysis of the resulting spectra. I analyseboth the potential observability of individual bispectra, and their correction due togeneral relativistic effects. It is clear from the results that lensing must be carefullyincluded in any attempt at accurately extracting primordial bispectra.

AB - The concordance model of cosmology is remarkable for its apparent simplicity, andvast range of predictions. Yet its two most well known and infamous ingredients,dark energy and inflation, have so far avoided all attempts at direct observation. Evenso, theorists invent ever more exotic models, and experiments must keep up at anever increasing pace, preserving both precision and accuracy in the analysis.In this thesis I compute corrections to large scale structure observables, correctionswe expect solely due to general relativity. The calculations can be perceived in twoways. The pessimist will say these effects are unwanted systematics in the search forprimordial physics, the optimist will see it as a chance to test general relativity toever increasing precision. Regardless, these effects must be computed as part of theinterpretation of coming observations.I calculate the predicted bispectrum in galaxy number counts from general relativisticeffects. This includes in particular lensing, which will systematically shift theobserved bispectrum for observations of large scale structure. Furthermore, I developand explore a scheme for fast computation of the galaxy number count spectra, inthe flat-sky approximation.The last part of the work is a numerical analysis of the resulting spectra. I analyseboth the potential observability of individual bispectra, and their correction due togeneral relativistic effects. It is clear from the results that lensing must be carefullyincluded in any attempt at accurately extracting primordial bispectra.

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122806288805763

M3 - Ph.D. thesis

BT - Testing Cosmological Models

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -