writes "Astronomers have seen the aftermath of spectacular stellar explosions known as supernovae before, but no one had witnessed a star dying in real time — until now. While looking at another object in the spiral galaxy NGC 2770, using NASA's orbiting Swift telescope, scientists detected an extremely luminous blast of X-rays released by a supernova explosion. They alerted 8 other telescopes to turn their eyes on this first-of-its-kind event. 'We were looking at another, older supernova in the galaxy, when the one now known as SN 2008D went off. We would have missed it if it weren't for Swift's real-time capabilities, wide field of view, and numerous instruments.'"
Bad Astronomy has an excellent, well-illustrated story
about the discovery as well. I Don't Believe in Imaginary Property
contributes a link to the BBC's coverage
, and adds a nugget gleaned from Ars Technica: "SN 2007uy's collapse caused an X-ray burst of about 10^39 joules
, most likely due to the 'shock break out' when the energy of the core's collapse finally reached the neutron star's surface."