Non-linear relativistic effects on cosmological perturbations

Lead Research Organisation: University of Portsmouth
Department Name: Institute of Cosmology and Gravitation

Abstract

The growth of cosmological perturbations is usually studied either through perturbation theory or via non-linear simulations. In the former approach, the full effects of general relativity are included, but the calculations are limited to large scales where the perturbations are small. Conversely, simulations are able to follow the evolution on small scales, but the treatment of gravity is usually approximated as Newtonian. The focus of this project is to understand how a fully relativistic treatment affects the non-linear evolution of structure, and how this will impact our interpretation of the next generation of large scale structure data, such as the Square Kilometre Array (SKA).

The student will be building our recent advances in this area, including a consistent second order relativistic code and our understanding of how Newtonian simulations can be interpreted in a relativistic context. They will also work to determine how line-of sight effects, like gravitational lensing, can impact the observations on the largest scales.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N504245/1 01/10/2015 30/09/2021
1998600 Studentship ST/N504245/1 01/10/2017 30/09/2021 Samuel Edward Lawrence
ST/R505018/1 01/10/2017 30/09/2021
1998600 Studentship ST/R505018/1 01/10/2017 30/09/2021 Samuel Edward Lawrence
 
Title Computer Programming 
Description In the above box there was not a suitable option. All options listed were related to biological sciences. I have learnt how to program in C and Python over the course of my PhD. 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? No  
Impact A second-order cosmological Boltzmann code will be developed that can simulate large-scale clustering statistics. The simulated data can then be used to compare the results of the next generation of galaxy redshift surveys. This would not be possible if I could not develop this tool. 
 
Description Doctor Christian Fidler 
Organisation RWTH Aachen University
Country Germany 
Sector Academic/University 
PI Contribution Together we have started to write parts of a module in a code, SONG, he helped develop.
Collaborator Contribution He hosted me over the course of a 4-month research visit to RWTH Aachen.
Impact Future paper.
Start Year 2019
 
Description Doctor Obinna Umeh 
Organisation University of Portsmouth
Country United Kingdom 
Sector Academic/University 
PI Contribution Secondary supervisor.
Collaborator Contribution Advised me over the course of my PhD. We meet weekly along with primary supervisor.
Impact Future paper.
Start Year 2017
 
Description Professor Robert Crittenden 
Organisation University of Portsmouth
Country United Kingdom 
Sector Academic/University 
PI Contribution Primary supervisor
Collaborator Contribution My supervisor has guided me from the onset of my PhD which commenced October 2017. We have met on a weekly basis.
Impact Eventually a paper.
Start Year 2017
 
Description Ask a Scientist 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact School children and scientists were able to communicate on an instant-messaging platform. Students were able to ask questions about science, careers, education etc.
Year(s) Of Engagement Activity 2019
 
Description Croydon Astronomical Society Talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact I gave a talk on simulations in cosmology and how scientists can understand the Universe through this process.
Year(s) Of Engagement Activity 2019
 
Description Meet a Physicist 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact 60 College students visited the University and we did our best to portray our experiences studying and working within physics.
Year(s) Of Engagement Activity 2019
 
Description Stargazing 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Local Portsmouth residence were about to visit the dockyard where an event was hosted by our department. The evening consisted of expert panels, workshop activities etc.
Year(s) Of Engagement Activity 2018