Fireworks in the sky - 4 Gamma-ray bursts in one day

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On March 19, 2008, a total of 4 Gamma-Ray bursts (GRBs) were localized by the Swift satellite, of which 3 have been also independently detected by INTEGRAL. Among them, probably the brightest one we have seen since INTEGRAL and Swift are looking for bursts. This outburst occured at 7:12 a.m. in the morning of March 19, and if one would have looked at its position by chance, one could have seen it with the naked eye (peak brightness was about 5.6 mag in the optical). Also INTEGRAL detected this burst, probably caused by the Supernova explosion of a very massive star. Unfortunately it appeared not to be in the field of view of one of the imaging instruments, but was detected in the heavy shielding which encloses the SPI spectrometer. Many telescopes were pointed immediately at this GRB, revealing that it was located probably at redshift 0.94 (it happened when the Universe was less than half as old as today), which means a (luminosity) distance of about 7.5 billion light years away from us - imagine how bright it has to be, to be visible by naked eye at that distance. In fact, during its outburst, the GRB was 100 million billion times (10E17) brighter than our sun, and still 10,000 times brighter than the quasar 3C 273. A burst as bright as GRB 080319B which would happen in the centre of our Milkyway, would appear much brighter than the Sun. Unfortunately, such an event is assumed to be rather rare - we expect to have one Gamma-Ray Burst in the Milkyway every 100,000 to 1,000,000 years, and a bright Gamma-Ray Burst would have to direct its emission towards us, thus one would have to wait on average 1 to 100 billion years for such an event in our own Galaxy.

For a summary of the findings on the 4 bursts of March 19, see
http://gcn.gsfc.nasa.gov/other/080319.gcn3
For the report about what INTEGRAL saw:
http://gcn.gsfc.nasa.gov/gcn3/7450.gcn3
and see the impressive light curve extracted from the INTEGRAL SPI-ACS
For a short movie of the outburst in the optical, see the outburst of GRB080319B

The analysis of GRB080319B led to the following publication in the science magazin Nature:
Broadband observations of the naked-eye gamma-ray burst GRB 080319B

In case of questions and comments: contact me at the APC. The images on this page are artist's impressions of a GRB (Credit: NASA/Zhang & Woosley).

Last update: March 26, 2008 by V. Beckmann