Oscar Wistemar

Hi! I'm a PhD student in Astrophysics in the Particle Physics, Astrophysics, and Medical Imaging division at KTH, with my supervisors: Prof. Felix Ryde and Dr. Filip Alamaa.

My research is focused on the most energetic events in the known universe, Gamma-Ray Bursts (GRBs). Originating from the creation of black holes during core-collapse supernoave or binary neutron star mergers, they radiate the amount of energy the Sun will in its lifetime during tens of seconds! The radiation comes from the ultra-relativistic jet launched by the newly created central engine (black hole or neutron star), but what process creates the emission in the jet is still unknown. In our group we investiagte the observed high-energy radiation to understand the emission process better. We do this in the framework of a radiation-mediated shock (RMS) occurring in the jet, leading to photospheric emission.

Our work covers both observations and theory of GRBs. Through data analysis we fit the KRA (Kompaneets RMS approximation) model to observed GRB data, and infer properties of the RMS. We then consider theoretical aspects of a photosphere and an RMS, to infer properties of the jet and the central engine.

For the past two years I have been a teaching assistant in Vector Analysis (SI1146) and Mathematical Methods in Physics (SI1200).