Michael Burgess joined the Oskar Klein Centre in mid-January as OKC fellow, after finishing his PhD in the US. His specialty is GRBs and that is why he joined with Felix Ryde in the KTH group.
The Fermi satellite was launched in 2008 and since then it has continuously monitored the sky at gamma-ray energies above 100 MeV. Most of the sources detected at these energies are blazars, Active Galactic Nuclei in which the accretion onto a supermassive black hole also leads to the launching of two opposite relativistic jets.
On April 27th this year, an e-mail alert was sent around signifying the detection of yet another GRB. Yet this event was like no other challenging all our models.
It is the Knut och Alice Wallenbergs foundation that grants a 5-year long project for finding and studying supernovae. The OKC are already since the beginning of this year members of the intermediate Palomar
Transient Factory (iPTF) – a supernova search aimed at finding supernovae soon after explosion. This is a pathfinder for the next generation of this project – the Zwicky Transient Facility (ZTF). The 30 million grant from KAW will now enable OKC astronomers and physicists to play a leading role in that project.
On June 3rd 2013 at 15:49 UT NASA’s Swift satellite detected an intense flash of γ -rays known as a short γ-ray burst. Follow-up observations by the Hubble Space Telescope revealed infrared emission that was present 9 days after the burst, but had faded away after 30 days.
On 27 April, an incredible opportunity was given to GRB science detectives. As the spring was outbursting here in Stockholm the explosion of a distant star almost blinded the Gamma ray Burst Monitor (GBM) detectors on board the Fermi satellite. GRB130427 is the brightest GRB ever detected in the keV – MeV band and the longest lasting in the GeV energy range: Fermi Large Area Telescope (LAT) could detect it for hours after the trigger.
Elena Moretti is the first of the about 300 applicants who was selected to become an Oskar Klein Fellow this year. She comes from a little country-side town, called Cartura, on the south of Padua in Italy where she graduated in physics in 2006. She got her PhD in Trieste where she worked with the AGILE and Fermi experiments on GRBs. She developed a method that was used to calculate the flux upper limits on the GRB emission that was used in both experiments.
The results presented at the III Fermi symposium in Rome reflected, in particular, what a magnificent instrument the Fermi LAT is for observing active galactic nuclei and pulsars. The 2 source catalogue 2FGL was presented and will soon be released with 1888 sources. Much attention was given to the blazar 3C454.3 which has been monitored since the launch and has undergone a series of very bright outbursts.
One of the many research topics at OKC is the study of gamma-ray bursts (GRBs). Several aspects of them are studied, such as the gamma-ray and X-ray emission, the afterglow emission, and the interaction between the bursts and the circumburst medium.
In a recent paper based on observations with the Fermi Gamma-ray Space Telescope it is argued that the main emission during the first few minutes of GRBs is dominated by the jet photosphere and that there is significant amount of energy dissipation close to the photosphere. This result is significant for our understanding of physics of GRB jets.