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 ››

Welcome the new director!

After eight years of existence, the Oskar Klein Centre of cosmoparticle physics ranks among the most dynamic and successful European research centres in the field. We are proud for having hosted outstanding postdocs and recruited world leading researchers.
Today, a new chapter in the OKC success story is about to unfold: it is time for me to pass on the baton to Hiranya Peiris, as she starts her journey as the new director of the centre.

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 ››

ATLAS Thesis Award goes to the Dark Side

Ruth Pöttgen is a postdoctoral researcher in the ATLAS group at Stockholm University. In 2015, she obtained her Ph.D. at the Johannes Gutenberg – University in Mainz, Germany, for her thesis on a “Search for Dark Matter in Events with a highly energetic jet and missing transverse momentum at a centre-of-mass energy of 8 TeV with the ATLAS Detector”. At the ATLAS collaboration meeting in February, Ruth was awarded one out of 4 ATLAS Thesis Awards for outstanding contributions to the ATLAS-Experiment in the context of a Ph.D. thesis; more than 100 theses were eligible.

Gravitational waves finally detected

It seems that nearly exactly 100 years after their prediction by Albert Einstein, Gravitational Waves have finally been directly detected for the first time. Speakers of the LIGO experiment announced yesterday that they have witnessed the final stages of the inspiral and merger of a massive black hole binary system. This marks the beginning of a new type of astronomy with gravitational waves that allows to explore a so-far completely unknown side of the Universe.

As we turn the page to a new year

As we close the book on 2015 we can again look back at a year of exciting science and great accomplishments by members of the Oskar Klein Centre for Cosmoparticle Physics. As in previous years, OKCers feature very prominently in the list of the most cited astrophysics and cosmology papers led by Swedish scientists published during the year. The list was compiled by Robert Cumming in populärastronomi and appears in today’s issue. In fact, half of top-10 2015 publications originate in our centre, starting … 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.