Ponente
Descripción
In 2017, the IceCube observatory associated (at a significance level of 3σ) a high-energy (HE, E ≥ 100 TeV) muon neutrino temporarily and spatially coinciding with an electromagnetic flare in blazar TXS 0506+056. Since then, no individual blazar-neutrino association at the same level of significance has been made. In November 2010, flat-spectrum radio quasar (FSRQ) 3C 454.3 had an exceptionally bright gamma-ray flare (~100 times brighter than the flare of TXS 0506+056), which made it the brightest object in the gamma-ray sky seen by Fermi-LAT. We analyse the rich set of then-collected multiwavelength data from 3C 454.3 by various telescopes (from optical to gamma-ray band) and model the observable electromagnetic and neutrino emission from 3C 454.3, enquiring what level of neutrino flux we could expect from such a flare. Utilising the Fermi-LAT light curves from the light curve repository and extrapolating the model of 3C 454.3 to all Fermi-LAT FSRQs we show that they can contribute to the HE astrophysical neutrino flux only at a level of $\sim 0.5$%, explaining the rarity of events such as the one from TXS 0506+056. We note also that the energy-loss and acceleration timescale of protons responsible for the production of HE neutrinos may be up to $\sim10^{3}$ times slower than the characteristic timescales of leptonic processes responsible for the electromagnetic flares. This may cause a substantial months-to-years delay of blazar-associated neutrino emission with respect to the major blazar flares. We present the results of our first search for this lagging blazar emission, cross-matching Fermi-LAT light curves with the IceCat-1 catalogue of HE neutrinos.
