If I remember correctly, the neutrino signal from 1987A was not discovered until several days after the optical SN discovery. I mean, it did happen before Shelton's observation, but there was no real-time alert.

Actually, the Caltech team is twisting history here quite a lot… Every long Gamma-Ray Burst is an eminent signal of an exploding star. And the best claim for immediate detection is XRF 060218/SN 2006aj. In that case, the X-ray Outburst actually triggered Swift (with XRO 080109, it was discovered in ground analysis hours later), and both Swift's UVOT as well as the ROTSE robotic telescope discovered optical emission just 100 seconds or so after the begninning of the outburst. But that was not discovered by Caltech, so they are downplaying it…

@Astrofiend: This is not the only team reporting observations!! Do check out these papers too:

http://arxiv.org/abs/0805.1188
(This team was the first to identify that the new optical source was, indeed, a supernova)
http://arxiv.org/abs/0805.2201
(This team has sensitive limits just hours before the X-ray outburst, and also were the first to correctly identify this as a Type Ib SN, not Ic.)

Yeah – I reckon you could debate this point with support going either way. My take on it is that, while the neutrinos were detected at three separate observatories, they didn't quite know what they had seen for a little while. The 'discovery' was attributed to a visible light observation by Shelton, I think.

In the latest case, the X-ray burst arrived and was observed, signaling the imminent arrival of the optical component of the radiation. After reading the paper in question in 'Nature', the authors state "…Simultaneous observations of the field with the co-aligned Ultraviolet/Optical Telescope (UVOT) on board Swift showed no evidence for a contemporaneous counterpart [to the X-ray outburst]. However, UVOT observations just 1.4 h after the outburst revealed a brightening ultraviolet/optical counterpart. Subsequent ground-based optical observations also uncovered a coincident source."

So I guess they're claiming that, unlike for sn1987a, they witnessed the first actual supernova light-curve rising from the baseline to full intensity from the very first moment the optical signal came through .

I guess we will find out that this is a "first" based on some other criteria.

With that said, it may be that they have determined that SWIFT has been continuously trained on that area starting prior to the event, even if not focused on the original star itself. I guess that would beat out the previous first.

Great to see that this much firepower was brought to bear on the event! hopefully when the Large Synoptic Survey Telescope goes online, these sort of amazing observations will become much more frequent…

The neutrino burst from 1987A (in the Large Magellanic cloud) was detected in the US and Japan, and the time of the optical burst was bracketed by observations from Albert Jones in New Zealand and Ian Shelton at Las Campanas in Chile.

I would argue the detection of the neutrino burst constitutes a star "caught in the act" of going supernova.

Something for the historians to sort out, I suppose.

Still, this is a wonderful discovery. Can't wait to hear what they learn from this!