Tag Archives: dark energy

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?
I arrived at the Oskar Klein Centre in September 2009, and it has been both enjoyable and stimulating. Much of my time has been spent preparing a computer code to model the cosmological distribution of galaxy clusters in great detail, to be used for a number of projects. At present I am mainly working on utilizing the code in the different projects and preparing resulting articles, so although it’s been slow going periodically things are now coming together. Some good joint projects also appear to be coming together in the near future, which I think will be excellent.

Why did you choose the OKC for doing a postdoc?
I chose the OKC knowing the excellent facilities here, the quality/profile of the group and also the rather generous funding in the Oskar Klein Fellowship. The broad approach of the centre appealed to me and was a strong reason for applying.

What is your field of research? Can you describe the project/projects in which you are involved?

My general field is cosmology, both towards the observational and towards the theoretical. The projects I am involved in centre largely around multi-consistent analysis and testing of beyond-concordance cosmology.

One area is clusters of galaxies, where I work on cosmological constraints from the XMM Cluster Survey (XCS) and the XXL Survey. Both are X-ray surveys of galaxy clusters based on XMM-Newton images. Continue reading Interview with Martin Sahlén

Nobel Prize in Physics to Supernova Cosmology

The Royal Swedish Academy of Science announced today the Nobel Prize in Physics for 2011, something that made us at the Oskar Klein Centre very proud indeed. The Prize goes to the two teams who discovered the present acceleration of the universe using supernovae as standard candles: the Supernovae Cosmology Project, in the person of Saul Perlmutter, and The High-z Supernova Search Team in the persons of Adam G. Riess and Brian P. Schmidt.
Ariel Goobar, professor at the Oskar Klein Centre, has been part of the Supernovae Cosmology Project since its beginning, when directly after his PhD defense in 1991, started a PostDoc at the LBL with Saul Perlmutter.
– I left particle physics to work on a murky field that nobody thought made any sense. says Ariel Goobar – I have worked with Saul in this project for almost 20 years now, it feels great to have been part of this journey from the very bumpy beginning when nobody thought these measurements were possible to do, until today’s monumental recognition. Continue reading Nobel Prize in Physics to Supernova Cosmology

Observing supernovae with the Gran Telescopio Canarias

Rahman Amanullah is one of the post doc working within the Oskar Klein Centre. He is currently spending a few nights observing supernovae in the Canarias so I asked him to tell me what they are up.

We are just about to finish our second night at the world’s largest optical telescope, the 10.4m Gran Telescopio Canarias (GTC) on the summit of the island of La Palma. For me personally, observing surely confirms that the only difference between children and scientists are the prices of their toys. The pricetag of the GTC is roughly 650000 times more than the telescope I got in the 8th grade, but on the other hand it also has about 10000 times light collecting capability. Continue reading Observing supernovae with the Gran Telescopio Canarias

The Return of de Sitter

The return of De Sitter During the last three weeks, we were visited by an impressive list of cosmologists trying to make sense of what is driving the present accelerated expansion of the Universe. The return of De Sitter, this is the name of the NORDITA workshop organized by OKC members Fawad Hassan and Ariel Goobar, together with Stefan Hofmann from LMU in Munich.
I asked Ariel Goobar, professor at OKC, and Stefan Sjörs, a PhD student in the Cosmology, Astroparticle Physics and String Theory group, to tell us about the conference.

Continue reading The Return of de Sitter

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 Continue reading Welcome to the Oskar Klein Centre blog