Category Archives: Science at OKC

From PoGOLite to PoGO+

As avid readers of this blog, you no doubt remember PoGOLite - a balloon-borne hard X-ray polarisation mission which is part of the Swedish National Space Board national programme for balloon and sounding rocket research at the Esrange Space Centre. After a number of frustrating set-backs (broken balloons, bad weather, ...), the Crab was successfully observed in July 2013 - providing the first measurement of the polarisation of emissions in the 20 - 120 keV energy band. Technical difficulties encountered during the flight meant that the polarisation parameters could only … Continue Reading ››

Measuring the supernova rate in the early Universe by using galaxy clusters as gravitational telescopes

Supernovae are very rare phenomena in the Universe and their transient nature made them difficult to find for a long time. So, it is not surprising that the discovery rate was around two supernovae per month 30 years ago. Today, we are able to find supernovae daily. For example, the Intermediate Palomar Transient Factory, in which our group at the Oskar Klein Centre is involved, has discovered almost 3000 supernovae in the last few years. However, these supernovae are all relatively nearby, since the survey is not sensitive … Continue Reading ››

Hunting light dark matter with gamma rays

Physicists around the globe are working relentlessly to pin down the nature of dark matter. This enigmatic entity hides itself from our view as it does neither emit nor absorb any radiation. It only reveals itself through its gravitational interaction. With a new analysis of data from NASA’s gamma-ray large area telescope (LAT) on board the Fermi satellite, we have now come closer to test very light dark matter candidates. Many regard the astrophysical evidence for dark matter as evidence for yet undiscovered fundamental particles. Well-motivated theories suggest that these particles … Continue Reading ››

The XENON1T inauguration

Dark matter is one of the basic ingredients of the Universe, and searches to detect it in laboratory-based experiments are being conducted since decades. However, until today dark matter has been observed via its gravitational interactions that govern the dynamics of the Cosmos at all length-scales. In 2014, with a grant of the Knut and Alice Wallenberg foundation, OKC has joined an international collaboration, called XENON, that builds and operates detectors to find the elusive dark matter particles in the laboratory.