Göttingen 2025 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 14: Astrophysics II

EP 14.6: Vortrag

Freitag, 4. April 2025, 12:15–12:30, ZHG101

Can We Analytically Predict the Variability of Blazars? — •Vito Aberham and Felix Spanier — Institut für Theoretische Astrophysik, Universität Heidelberg, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany

Active galactic nuclei (AGN) are known for their variable emission. We apply an evolving two-zone model to their hybrid jets containing both electrons and protons, allowing for the emission of neutrinos. The dominant source of variability, these AGN jets are characterized by the main cooling process triggering the SED’s high-energy peak. We choose blazars with proton synchrotron radiation as the predominant emission mechanism for high energies, while electron synchrotron radiation drives the low energy emission. We defer the case of cascades dominating the emission to future work. Including both their acceleration and cooling in the respective zones, we obtain the particle distributions by solving two coupled PDEs while neglecting the effect of second-order Fermi acceleration. We then calculate the photon density, which, combined with the proton distribution, yields the emerging neutrino flux. We infer the according light curves and neutrino fluxes in specific energy bands, enabling comparisons to a wide range of observed blazars. To fully leverage our analytical result’s dependency on the free model parameters, we introduce a public tool capable of simulating blazar flares, which allows for rapidly cross-checking numerical simulations at low computational cost. We thus developed the ability to not only predict the variability of any proton-synchrotron dominated blazar analytically but also enhance the quality of simulations.

Keywords: Active Galactic Nuclei; Relativistic jets; Non-thermal radiation; Neutrinos; Blazar flares