Speaker
Description
TXS 0506+056 is the first blazar associated with a high-energy neutrino detection (IceCube-170922A) in 2017. Notably, no immediate radio brightening accompanied this neutrino producing γ-ray flare but instead, a major radio outburst occurred about 2.5 years later. We investigate whether the 2017 flare accompanied by a high-energy neutrino event can lead to such a delayed radio flare. Using parameters from a published multi-messenger model of the 2017 flare, we simulate the evolution of a relativistic “blob” of plasma ejected during the flare. We propose a two-stage scenario in which the blob travels outward in the jet and becomes transparent, then undergoes a fresh particle acceleration in the optically thin regime on parsec scales. A mild deceleration of the jet (as hinted by very-long-baseline radio imaging) is also introduced. This re-acceleration model reproduces the time lag and spectrum of the radio flare. Our results suggest that production of high-energy neutrinos in blazars can lead to a delayed radio flare, but only after the emitting region propagates downstream and encounters new energization.
