NASA's Fermi sees largest gamma-ray burst

William Atkins
Friday, 20 February 2009 23:14

Science - Space

NASA reported on February 19, 2009 that its Fermi Gamma-ray Space Telescope saw the first gamma-ray burst ever seen in high resolution. But, the big news is that the GRB is the largest ever recorded, having the "greatest total energy, the fastest motions and the highest energy initial emissions ever seen."


The gamma-ray burst (GRB) that the Large Area Telescope (LAT, one of Fermi’s instruments) saw was designated GRB 080916C.

The observation of the main explosion occurred at approximately 7:13 p.m. Eastern Daylight Time (EDT) on September 15, 2008 (with the observation begin date and time at 2008-265-01:29:02.327380 and the end date and time at 2008-265-01:49:57.326760).

The explosion was seen in the constellation Carina.

At the same time, the Gamma-ray Burst Monitor, another instrument onboard Fermi, recorded an initial energy range from the blast (explosion) that was between 3,000 times to over 5 billion times that of visible light.

The blast, according to calculations performed by the Fermi team, had an equivalent power of about 9,000 ordinary supernovae (assuming all of the energy was emitted uniformly in all directions).

In this case, however, the jets from the gamma-ray burst was directed in tight directions, which makes its energy output even more amazing.

A video of the gamma-ray burst is found on the Science@NASA website “Extreme Gamma-ray Burst.” The six-second video shows a compression of about eight minutes of observations made by the Large Area Telescope (LAT) onboard Fermi.

An image of the afterglow, as imaged by Fermi’s Gamma-Ray Burst Optical/Near-Infrared Detector, or GROND, is also provided.

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