High Energy Neutrinos from Recent Blazar Flares

Understand

The energy density of cosmic neutrinos measured by IceCube matches the one observed by Fermi in extragalactic photons that predominantly originate in blazars.

• This has inspired attempts to match Fermi sources with IceCube neutrinos.
• A spatial association combined with a coincidence in time with a flaring source may represent a smoking gun for the origin of the IceCube flux.
• In June 2015, the Fermi Large Area Telescope observed an intense flare from blazar 3C 279 that exceeded the steady flux of the source by a factor of forty for the duration of a day.