Fast TeV variability from misaligned minijets in the jet of M87

TL;DR

This paper proposes a model where misaligned minijets within the jet of M87 produce rapid TeV flares observable despite the jet's orientation, explaining fast variability in radio galaxies.

Contribution

The study introduces a minijet model for TeV flares in misaligned jets, extending previous models to explain observations in M87 as a misaligned blazar.

Findings

About half of the minijets beam emission outside the jet cone.

Off-axis minijets produce rapidly evolving TeV flares.

The TeV flaring in M87 aligns with the misaligned blazar scenario.

Abstract

The jet of the radio galaxy M87 is misaligned, resulting in a Doppler factor delta~1 for emission of plasma moving parallel to the jet. This makes the observed fast TeV flares on timescales of t_v~5R_g/c harder to understand as emission from the jet. In previous work, we have proposed a jets-in-a-jet model for the ultra-fast TeV flares with t_v<<R_g/c seen in Mrk 501 and PKS 2155-304. Here, we show that about half of the minijets beam their emission outside the jet cone. Minijets emitting off the jet axis result in rapidly evolving TeV (and maybe lower energy) flares that can be observed in nearby radio galaxies. The TeV flaring from M87 fits well into this picture, if M87 is a misaligned blazar.