This image shows the afterglow of GRB 090423 (red source in the centre) and was created from images taken in the z, Y and J filters at Gemini-South and VLT (credit: A. J. Levan).In this week's edition of the science journal Nature, two international teams of astronomers report their observations of the most distant object yet seen in the Universe. Dubbed GRB 090423, the record-breaker is an example of a gamma-ray burst, the brightest and most violent explosions known to exist. The explosion is thought to accompany the catastrophic death of a very massive star as it ended its life, and is triggered by the centre of the star collapsing to form a black hole.
"This observation allows us to begin exploring the last blank space on our map of the Universe", said Professor Nial Tanvir, who led one of the teams. Although the gamma-ray burst itself occurred about 630 million years after the Big Bang, it is so far away (about 13.1 billion light years) that the light from the explosion only arrived at the Earth in April of this year. "It is tremendously exciting to be looking back in time to an era when the first stars were just switching on", commented team member Dr Andrew Levan.
Much of this light was in the form of very high energy gamma-ray radiation, which triggered the detectors on a NASA satellite called Swift. Following up on the automatic announcement from Swift several of the world's largest telescopes turned to the region of the sky within the next minutes and hours and located the faint, fading afterglow of the GRB. Detailed analysis revealed that the afterglow was seen only in infrared light and not in the normal optical. This was the clue that the burst came from very great distance.
CONTACTS
Prof Nial Tanvir, University of Leicester, UK
email: nrt3@star.le.ac.uk
mobile: 07980 136499
office: 0116 2231217
home: 01763 241841
Dr Andrew Levan, University of Warwick, UK e
mail: a.j.levan@warwick.ac.uk
mobile: 07714 250373
Prof Derek Fox, Penn State University, USA
email: dfox@astro.psu.edu
phone: +1 814 863 4989
Prof. Ralph Wijers, University of Amsterdam, NL
email: ralph.wijers@uva.nl
mobile: +31 (0)652654218
FURTHER INFORMATION
Nature press notice
GRB 090423 background FAQ
Figures from paper
LINKS
Swift satellite
Swift UK site
United Kingdom Infrared Telescope
Gemini Telescopes
ESO Very Large Telescope
eSTAR automated observing technology
