Astrophysical Simulations for Uncovering Signatures of Gravity
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AbstractEinstein's theory of general relativity is currently our best model for how gravity works. It can be used to predict motions of planets, the speed-up of clocks on GPS satellites, and gravitational waves. General relativity has been used to model the history and expansion of the Universe as a whole, but on these vast scales, problems start appearing. To make the theory match our observations, we have to add two components we don't know much about, and that we have never observed: dark matter and dark energy. To explain the shortcomings of general relativity, it is important to explore alternative theories of gravity. In my work, I have used special designed computer simulations to better understand specific theories of modified gravity, and to investigate the simplifying assumptions that are often applied by researchers studying these theories. I have also studied possible new observational signatures that can be used to distinguish between different gravitational theories. My work explores new phenomena in one specific modified gravity theory, called disformal quintessence. Furthermore, it is showed that in some cases one cannot ignore commonly neglected terms in the equations.
List of papers
|Paper I: Robert Hagala, Claudio Llinares, and David F. Mota ‘Cosmic Tsunamis in Modified Gravity: Scalar waves disrupting screening mechanisms’. In: Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.101301. arXiv: 1607.02600. The article is included in the thesis. Also available in DUO at http://urn.nb.no/URN:NBN:no-62791|
|Paper II: Claudio Llinares, Robert Hagala, and David F. Mota ‘Non-linear Phenomenology of Disformally Coupled Quintessence’. Monthly Notices of the Royal Astronomical Society, 2019, stz2710. DOI: 10.1093/mnras/stz2710. arXiv: 1902.02125. The article is included in the thesis. Also available at https://doi.org/10.1093/mnras/stz2710|
|Paper III: Robert Hagala, Claudio Llinares, and David F. Mota ‘The Slingshot Effect as a Probe of Transverse Motions of Galaxies’. In: Astronomy & Astrophysics 628, A30 (2019). DOI: 10.1051/0004-6361/201935261. arXiv: 1907.01429. The article is included in the thesis. Also available in DUO at: http://urn.nb.no/URN:NBN:no-73679|