22-30 July 2021
North-West University
Africa/Johannesburg timezone
More Information Coming Soon

Time-Dependent Modeling of Blazar Spectral Variability with Diffusive Shock Acceleration

27 Jul 2021, 11:30
Potchefstroom Campus (North-West University)

Potchefstroom Campus

North-West University

Oral Presentation Track D1 - Astrophysics Astrophysics


Markus Bottcher (University of North West)


Jets in blazars are an excellent forum for studying acceleration at relativistic
MHD shocks, since this process is likely to spawn the highly-variable emission
seen across the electromagnetic spectrum from radio to gamma-rays. Our recent
work on combining time-dependent multi-wavelength leptonic emission models with
complete simulated thermal + non-thermal particle distributions from shock
acceleration theory has resulted in new insights into plasma conditions in
AGN jets. This has demonstrated the ability to infer the plasma density, and
suggested the interpretation that turbulence levels decline with remoteness from
jet shocks, with a significant role for non-gyroresonant diffusion. Using our
time-dependent two-zone construction, we are able to model together both extended,
enhanced emission states from larger radiative regions, and prompt flare events
in select Fermi-LAT and TeV blazars. In this contribution, I present recent
applications of this simulation framework to AstroSAT and multi-wavelength
observations of the prototypical VHE gamma-ray blazar 1ES 1959+650 and
NuSTAR and multi-wavelength observations of the high-redshift FSRQ PKS 0537-286.
A prime goal is to ascertain whether such flares are truly associated with prompt
shock acceleration activity in relatively confined regions. The results illustrate
how parametric degeneracies in shock acceleration conditions can lead to refined
determinations of the plasma density and particle diffusion character in blazar jets.

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Primary author

Markus Bottcher (University of North West)

Presentation Materials