Slashdot Mirror
Fermi and Swift Observe Record-setting Gamma Ray Burst
symbolset writes "Phys.org shares a visual image of a 'shockingly bright' gamma ray burst observed April 27th, labelled GRB 130427A and subsequently observed by ground optical and radio telescopes. One gamma ray photon from the event measured 94 billion electron volts — three times the previous record. The burst lasted four hours and was observable for most of a day — another record. Typical duration of a gamma ray burst is from 10 milliseconds to a few minutes. Astronomers will now train optical telescopes on the spot searching for the supernova expected to have caused it — typically one is observed some few days after the burst. They expect to find one by the middle of May. The event occurred about 3.6 billion lightyears distant which is fairly close as gamma ray bursts go. Click on the GIF to view the actual burst."
No, although that was entertained (by some) in the fairly long history of these bursts.
In the early days (after GRB were detected by US satellites sent up to look for nuclear explosions) there were lots of theories, as we knew basically nothing about them. The consensus was that GRB were probably fairly close to us, in the galaxy (which kept the burst energy reasonable). The early satellites could only see the brightest bursts, so there weren't many bursts observed, and statistics were very poor, so you couldn't say much more. (At this time I remember some people proposing primordial black hole explanations.) One of the major goals of the Compton Space Telescope BATSE experiment was to be sensitive enough to GRB to be able to observe hundreds to thousands of them, with decent positions, enough data so that you should be able to see the Milky Way (the galactic disk) in the burst locations (i.e., that you would see more bursts along the Milky Way in the sky than in other directions). At the time, the consensus opinion was very strongly that BATSE would see the plane of the Milky Way in the aggregate burst positions, as they accumulated.
The experiment was flown and worked well and recorded an isotropic (random) distribution of bursts. (So much for conventional wisdom.) This meant that the bursts were either very far away (and thus very powerful) or very close (and thus relatively weak, weak enough that you could only see them up to a few light years, where everything is in the galactic disk, and thus can look random in direction, the way the brightest stars in the night sky appear more-or-less random in direction). I actually toyed around with an extraterrestrial intelligence explanation for close bursts at that time (the bursts would be some side effect of power generation or space travel, which would have implied that the ETIs were close and ubiquitous), but most people started thinking about extremely distant (to be random), and thus very powerful events. (IIRC, this was bad but not quite fatal for the primordial black hole explanation, as those bursts are strong enough that you would expect to see the galactic disk in the accumulated BATSE data, but maybe you could adjust things enough to get around that.)
This conundrum was resolved by the orbiting Swift telescope, which could not only see GRB, but could report a position back to Earth quickly enough to train an optical telescope on the spot within a few seconds. This was flown, and some GRBs were observed in the optical. (This also required some serious work on rapid response optical telescopes.) Swift + optical meant that we knew their positions very accurately, so the biggest telescopes could be used to see where, exactly, they were coming from (which turned out to be distant galaxies) and thus get a red shift, and thus a distance (the GRB of the OP is apparently at a red shift of 0.34). That, among other things, showed very clearly that these bursts could not be primordial black holes (or local ETI!), as those are much too weak to see bursting across cosmological distances.