Delta på disputasen
PhD disputasen og prøveforelesningen vil foregå 100% fysisk. Rommet åpnes for deltakelse like før disputasen starter, og stenger for nye deltakere omtrent 15 minutter etter at disputasen har startet.
Delta på prøveforelesning - 13. februar kl. 10:15 (Aud. 209, Svein Rosselands Hus)
"Using stellar streams to probe the nature of dark matter"
Kreeringssammendrag
Strålingen fra stjerner og aktive galaktiske kjerner spiller en viktig rolle i galakseutviklingen. I min avhandling viser jeg hvordan ioniserende ultrafiolett stråling kan oppvarme og ionisere en galakses gassreservoir og dermed påvirke dannelseshastigheten til nye stjerner. Disse endringene i stjernemasens oppbygging påvirker deretter mange av en galakses egenskaper.
Hovedfunn:
My PhD thesis investigates how ionising ultraviolet (UV) radiation from distant galaxies and active galactic nuclei, summarised as UV background radiation, and from locally formed stars impact the evolution of low mass dwarf galaxies (DGs) by means of numerical radiative transfer (RT) simulations.
The first part of the thesis goes through the development of a new numerical scheme for RT and the discretisation of the source spectrum. These methods are designed for galactic scale simulations with a strong focus on computational efficiency. The second part compares our RT simulation of a group of DGs to a simulation of the same group without radiative transfer. We find that radiation from the UV background has a significant impact on the rate at which stars are formed within the early universe. At later times radiation form local stars heats the gas within the DGs, this results in a less bursty star formation rate and an overall suppression of the star formation. The total stellar mass between these two simulation runs only differs by a factor of about two to three. These changes in the stellar mass build up subsequently influence many properties of these DGs.
