It's a very merry gamma ray burst Christmas

Posted by fi17 at Dec 06, 2011 04:20 PM |
Dr Kim Page's enjoyment of last year's Dr Who Christmas Special was cruelly interrupted - by an exploding star
It's a very merry gamma ray burst Christmas

Artist's impression of the Christmas Day Burst. Credit: A. Simonnet, NASA, E/PO, Sonoma State University

A powerful Gamma Ray Burst (GRB) that was detected on Christmas Day last year has proved to be so extraordinary that scientists studying the phenomena had to come up with a whole new theory to explain it. GRBs are fierce bursts of high-energy gamma rays originating in deep space and distant galaxies, usually associated with stars exploding or violently colliding. But the Christmas Day Burst, as it has been named, lasted far longer than most GRBs.

Dr Kim Page of our Department of Physics and Astronomy was the X-Ray scientist-on-call when the news of GRB 101225A - the Christmas Day Burst - came through. It turned out to be so interesting she didn't mind missing the end of Dr Who. Most GRBs are over in a few minutes, but GRB 101225A went on for over half an hour and produced a lot of heat along with typical gamma rays.

Dr Page was part of the team that investigated the Christmas Day Burst and came up with a new theory to explain it: a neutron star merging with the helium core of an evolved giant star. As the neutron star entered the atmosphere of its giant partner, the massive star expelled most of its hydrogen envelope. Later, when the stars' cores met and exploded, the ejected hydrogen was super-heated in the explosion, causing the distinctive heat signature seen after the Christmas Day Burst.

The GRB was detected by SWIFT, a satellite specially designed to pick up GRBs as they happen and includes a wide-area Burst Alert Telescope.

The findings of the investigation are published in the international science journal Nature.