14–24 Jul 2025
CICG - International Conference Centre - Geneva, Switzerland
Europe/Zurich timezone

SED evolution modeling of Mrk421 during its most violent year: insights from a stochastic acceleration model

16 Jul 2025, 16:35
15m
Room A

Room A

Talk Gamma-Ray Astrophysics GA

Speaker

Jayant Abhir (ETH Zurich)

Description

Blazars are highly variable sources and show variability down to minute time scales. The current generation of Imaging Atmospheric Cherenkov Telescopes like MAGIC are able to probe the spectra of the brightest blazars at short time scales, especially in their flaring states. In this work, we characterize the variability and daily Spectral Energy Distribution (SED) evolution of the archetypal TeV blazar Mrk421 using simultaneous MAGIC very high energy (VHE band, >100 GeV) and multi-wavelength (MWL) observations from radio all the way up to gamma ray bands during the Nov 2009 to June 2010 campaign.

Mrk421 displayed its strongest flare ever observed in February 2010 when VERITAS measured VHE flux of ~15 Crab units above 200 GeV. VLBA data unveils contemporaneous ejections of radio features for the first time for Mrk421. The variability and MWL cross-correlations were analyzed along with the temporal evolution of the daily SEDs to gain insights into the emission processes of this flare that exhibits unprecedented characteristics for the source. We model the source with a physically motivated single zone leptonic population and study the phenomenology and spectral evolution in the context of a stochastic acceleration scheme.

Collaboration(s) MAGIC Collaboration

Author

Jayant Abhir (ETH Zurich)

Co-authors

Dr Andrea Tramacere (Université de Genève) Axel Arbet-Engels (Max Planck Institute for Physics) David Paneque (Max Planck Institute for Physics, Munich) on behalf of the MAGIC Collaboration

Presentation materials