Abstract
The concordance model of cosmology is remarkable for its apparent simplicity, and
vast 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. Even
so, theorists invent ever more exotic models, and experiments must keep up at an
ever increasing pace, preserving both precision and accuracy in the analysis.
In this thesis I compute corrections to large scale structure observables, corrections
we expect solely due to general relativity. The calculations can be perceived in two
ways. The pessimist will say these effects are unwanted systematics in the search for
primordial physics, the optimist will see it as a chance to test general relativity to
ever increasing precision. Regardless, these effects must be computed as part of the
interpretation of coming observations.
I calculate the predicted bispectrum in galaxy number counts from general relativistic
effects. This includes in particular lensing, which will systematically shift the
observed bispectrum for observations of large scale structure. Furthermore, I develop
and explore a scheme for fast computation of the galaxy number count spectra, in
the flat-sky approximation.
The last part of the work is a numerical analysis of the resulting spectra. I analyse
both the potential observability of individual bispectra, and their correction due to
general relativistic effects. It is clear from the results that lensing must be carefully
included in any attempt at accurately extracting primordial bispectra.
vast 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. Even
so, theorists invent ever more exotic models, and experiments must keep up at an
ever increasing pace, preserving both precision and accuracy in the analysis.
In this thesis I compute corrections to large scale structure observables, corrections
we expect solely due to general relativity. The calculations can be perceived in two
ways. The pessimist will say these effects are unwanted systematics in the search for
primordial physics, the optimist will see it as a chance to test general relativity to
ever increasing precision. Regardless, these effects must be computed as part of the
interpretation of coming observations.
I calculate the predicted bispectrum in galaxy number counts from general relativistic
effects. This includes in particular lensing, which will systematically shift the
observed bispectrum for observations of large scale structure. Furthermore, I develop
and explore a scheme for fast computation of the galaxy number count spectra, in
the flat-sky approximation.
The last part of the work is a numerical analysis of the resulting spectra. I analyse
both the potential observability of individual bispectra, and their correction due to
general relativistic effects. It is clear from the results that lensing must be carefully
included in any attempt at accurately extracting primordial bispectra.
| Originalsprog | Engelsk |
|---|
| Forlag | The Niels Bohr Institute, Faculty of Science, University of Copenhagen |
|---|---|
| Status | Udgivet - 2017 |