Thursday, April 25, 2013

Bert and Ernie Step Out

Last August, I posted a piece about  two high energy (PeV, 10^{15} eV neutrinos that IceCube had observed.  The neutrinos had been announced at Neutrino 2012, the main scientific conference for neutrino enthusiasts.  Now, we (IceCube) has written a paper about the two events, which has been posted to the Cornell preprint server at  The events have not changed much, but we have spent the intervening months refining the reconstructions and evaluating the backgrounds.    We now know the energies much more accurately:  1.04 and 1.14 PeV respectively, with a 15% uncertainty.    1 PeV = 1,000,000,000,000,000 electron volts, compared to 120 electron volts for an electron moving through the wires in your house.

We are also hard at work at follow-up studies, but we're not ready to present these yet.

The two events have been given catchy names, which have been featured in a number of news & blog reports about the events.    The two event displays show the two events.  Each dot is an IceCube optical sensor that observed Cherenkov light from the charged particles produced in the neutrino interaction.  The colors show when the light arrived at the sensor (red = earliest, then yellow, green, blue...), and the size of the circle indicates the number of photons that were observed.

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