Speaker
Description
Active Galactic Nuclei (AGN) and their relativistic jets are among the most energetic astrophysical systems, serving as promising sites for particle acceleration and multi-messenger emission. Despite decades of study, the matter composition of AGN jets remains an open question. The particles inside an AGN jet can be accelerated to high energies via different mechanisms, including shocks, stochastic turbulent acceleration, and magnetic reconnection which can generate distinct multi-messenger observational signatures. These signatures can therefore serve as pivotal diagnostic tools for assessing the viability of different jet composition models in explaining the observed multi-messenger emission from AGN jets.
The detection of high-energy neutrinos from the direction of blazars like TXS 0506+056, has renewed the interest in hadronic and lepto-hadronic jet composition models, as these models allow neutrino production through mechanisms involving proton interaction. To connect such multi-messenger observations with realistic jet dynamics, numerical tools are required that can simultaneously evolve relativistic magneto-hydrodynamic (RMHD) flows and non-thermal particle populations.
We have developed a lepto-hadronic multi-zone framework for AGN jets and coupled it with RMHD jet simulations performed using the PLUTO code. This framework has been further extended through our newly developed proton Lagrangian particle module for PLUTO, which augments the existing leptonic particle module. We solve the cosmic ray transport equation and evolve non-thermal proton populations along with lepton populations within the evolving jet. By combining jet dynamics, and different particle cooling and acceleration mechanisms, our framework generates synthetic multi-wavelength photon and neutrino fluxes for different AGN jet scenarios. We apply this framework to disentangle the role of internal shocks and entrainment of proton-rich matter via jet-environment interactions in shaping the resulting photon and neutrino emission signatures. Our framework serves as a bridge between relativistic magneto-hydrodynamic simulations, lepto-hadronic modeling, and multi-messenger observations of AGN jets.