Browsing by Subject "General relativity"

Now showing items 1-3 of 3

    • Constraining modified gravity models with cosmological data 

      Hough, R. T. (North-West University (South Africa), 2020)
      In this dissertation, we looked at the cosmological constraints of some f(R)-modi ed gravity models, such as f(R) = Rn (our rst toy model), f(R) = R + Rn (our second toy model), and more realistic ones like the Starobinsky ...

    • The cosmological perturbed lightcone gauge 

      Elmardi, Maye (MDPI, 2018)
      The lightcone gauge is a set of what are called the observational coordinates adapted to our past lightcone. We develop this gauge by producing a perturbed spacetime metric that describes the geometry of our past lightcone ...

    • X-ray polarimetry with the Polarization Spectroscopic Telescope Array (PolSTAR) 

      Krawczynski, Henric S.; Böttcher, Markus; Stern, Daniel; Harrison, Fiona A.; Kislat, Fabian F. (Elsevier, 2016)
      This paper describes the Polarization Spectroscopic Telescope Array (PolSTAR), a mission proposed to NASA’s 2014 Small Explorer (SMEX) announcement of opportunity. PolSTAR measures the linear polarization of 3–50 keV ...