Position: 00 26 54.689 +18 55 41.3 (2000.0) D.W. Fox et al.At 1206UT on 2002 October 4 the HETE spacecraft detected a long gamma ray burst. Less than 10 minutes later the Caltech-NRAO GRB collaboration identifed a 15th magnitude optical transient in Pisces. This transient was still visible at around 18th magnitude as night fell in the UK and a number of observers obtained images. To our knowledge these were the first images of a GRB obtained from the UK.
Although known since the 1960s, the immense distance and power of GRBs was only established in 1997. Since then, as soon as one is detected (by astronomical satellites which respond to the characteristic high energy radiation which gives GRBs their name), a race begins with observers around the world trying to pinpoint its exact location before the afterglow fades from view after only a few hours. In this instance the afterglow was first seen in California, so observers in this country knew just where to look when night fell here.
The first successful detections were from Nick James in Essex and Mark Armstrong in Kent. They were closely followed by Tom Boles and Martin Mobberley in Suffolk, David Strange in Dorset, Peter Birtwhistle in Berkshire, Eddie Guscott also in Essex and observers at the University of Hertfordshire Observatory.
Dr Nial Tanvir, a researcher in GRBs at the University of Hertfordshire, alerted the network of backyard scientists during the afternoon, while simultaneously arranging for the burst to be observed by several of the UK's large overseas telescopes. "By putting together data from telescopes all around the world we can learn more about what causes GRBs, which at the moment is still a mystery. The favourite idea is that they violent ejections produced during the last moments in the life of some massive stars, just as they are in the process of collapsing to form black-holes. Because they are unpredictable and fade so fast, when they do occur we try to observe them with every telescope we can."
NASA takes the role of amateur astronomers in GRB research sufficiently seriously that it helps fund the liaison between the American Association of Variable Star Observers, and other amateur groups worldwide. In the UK, the coordination effort is led by Guy Hurst and The Astronomer magazine.
These pictures show the faint fading afterglow of GRB021004. The GRB afterglow only shows up as a faint spot of light, but that's because it is about 10 billion light years away, or three-quarters of the way to the edge of the observable universe. In fact at it's peak, a GRB radiates with the power of a million billion Suns! At 1206UT on 2002 October 4 the HETE spacecraft detected a long gamma ray burst. Less than 10 minutes later the Caltech-NRAO GRB collaboration identifed a 15th magnitude optical transient in Pisces. This transient was still visible at around 18th magnitude as night fell in the UK and a number of observers obtained images. To our knowledge these are the first UK detections of a GRB afterglow.
It seems that the redshift of this object is z=2.3 which works out to be around 11 to 12 billion light years away!