My area of research is astroparticle physics, the intersection of particle physics and astrophysics. Within this my main focus is neutrino astronomy: using high energy neutrinos to understand extreme environments in the universe, places where particle acceleration can occur such as the regions near black holes. Neutrinos and gravitational waves are part of the emerging field of multi-messenger astronomy that complements and expands our view of the universe beyond that provided by light.
I am a member of the IceCube Collaboration, which operates the IceCube Neutrino Observatory at the South Pole, Antarctica. From 2008 to 2018 I have been leader and co-leader of the point-source analysis working group in IceCube. A milestone on the road to neutrino astronomy was the discovery by IceCube in 2013 of the high-energy astrophysical neutrino flux. The flux includes neutrinos with energies greater than 1 PeV (10^15 electronvolts), the highest-energy neutrinos ever detected. Two of the most significant challenges in the field today are the precise characterization of this flux, and the identification of the sources which are producing it.
I am a member of the Oskar Klein Centre for Cosmoparticle Physics and deputy director since 2017. The OKC brings together particle physicists and astrophysicists, experimentalists and theorists, from Stockholm University and the KTH Royal Institute of Technology.