Tag Archives: cosmology

A shocked neighbor?!

Discovering exploding stars, supernovae, within hours from explosion opens new windows to study their nature. Last year, our group at the intermediate Palomar Transient Factory (iPTF) was involved in the study of the closest SNIa explosion in several decades, SN2014J. We have now a new exciting result - an early glimpse of ultraviolet light from a Type Ia supernova, iPTF14atg, reveals what appears to be a shocked neighboring star. The results published in the journal Nature uncover the nature of the kind of objects that are used as standard … Continue Reading ››

A close look a the nearest standard candle supernova in several decades

Supernova 2014J in the nearby galaxy M82 -less than 12 million light-years away- exploded on January 14, 2014 and was the closest ”standard candle” supernova since (at least) 42 years. An impressive coordinated observational effort orchestrated by the intermediate Palomar Transient Factory (iPTF) team and led by Ariel Goobar from the Oskar Klein Centre at Stockholm University (Goobar et al. 2014, The Astrophysical Journal Letters, 784, L12) provides important new clues into the nature of these explosions, as well as the environments where they take place. The … Continue Reading ››

Hubble Space Telescope images of a supernova in nearby galaxy M82

A new bright supernova exploded in the nearby galaxy M82 on January 14 this year, at a distance of approximately 11.5 million light–years from Earth, that makes it to the nearest "normal" Type Ia supernova discovered in the past 42 years. Its small distance together with the fact that the first observations were carried out only a few hours after the explosion, makes it in itself a very important astronomical object, since it allows to study the details of many aspects of these kind of objects that are so important … Continue Reading ››

The intermediate Palomar Transient Factory

In February this year the iPTF (intermediate Palomar Transient Factory) program was started.
This is a survey searching for optical transients using a robotic 1.2 meter telescope in California, and the Oskar Klein Centre is one of the participating institutes for the next 2 years. The aim is to discover transients – in particular supernovae – at an earlier stage than hitherto possible, hopefully within hours after the explosion. The concrete scientific question we want to address is the nature of the progenitor systems of supernovae, and this requires very early observations of these explosions, before the memory of the initial configuration gets lost.

Interview with Martin Sahlén

We continue our interview series of Oskar Klein Centre fellows. Today we meet Martin Sahlén, starting his third year around. Martin works in the CoPS, Cosmoparticle Physics Group.

When did you start working for the OKC, and how it is going so far?
arrived at the Oskar Klein Centre in September 2009, and it has been both enjoyable and stimulating. Much of my time has

Workshop: clusters of galaxies as cosmic laboratories

Galaxy clusters occupy a central role in the ongoing efforts to understand some of the greatest questions in particle astrophysics and cosmology: the nature of Dark Matter and Dark Energy. Moreover, these huge mass concentrations serve as Nature’s own telescopes, capable of amplifying faint high-redshift sources that would otherwise be beyond our reach. At the same time, the use of galaxy clusters as probes for fundamental physics requires a good understanding of the state of the intra-cluster medium.

Time for PhD thesis defenses at the Oskar Klein Center

This spring there have been several PhD theses defenses here at the Oskar Klein Center, and as much as we hate saying good bye to some of our best students, we are proud to have been part of their professional lives. Jakob Nordin, Sara Rydbeck, Yashar Akrami, Teresa Riehm and Henrik Johansson defended their theses this spring. We wish them all the best for their future life!

Welcome to the Oskar Klein Centre blog

As a way to communicate more quickly and efficiently between ourselves in the Oskar Klein Centre (OKC) and with the outside world, we have with the advice of Serena Nobili, responsible for OKC information and outreach, started this blog. Here you will now and then get updates on what is happening in the Centre, and in our research fields. I am presently at the Neutrino Telescopes workshop in Venice, and will soon give some comments and impressions of things … Continue Reading ››