Speaker
Description
Blazars, a subclass of active galactic nuclei with collimated jets of matter oriented at the observer, Earth. These jets produce radiation across the entire electromagnetic spectrum, in the form of two broad, non-thermal peaks. There are competing models capable of reproducing this radiation, which can be broadly categorised into two types: leptonic and lepto-hadronic, based on the exclusion or inclusion of protons in the jet, respectively. One effect that is sometimes neglected in hadronic models is the production of electron-positron pairs via the Bethe-Heitler process, whereby protons interact with photons to produce these pairs. These leptons, with their energy unrestricted by classical acceleration mechanisms, may therefore produce higher energy radiation. This radiation can relax constraints in the parameter space, a common problem faced by leptohadronic models.
This study involves the implementation of a recently published semi-analytical model for Bethe-Heitler pair production, which significantly reduces the computational cost of simulating this process. With this having been implemented, a pipeline is being written to fit blazar spectra to multi-wavelength observations, using the Gammapy Python package to perform joint fits on quasi-simultaneous observations using a full lepto-hadronic model. Currently, only ultraviolet, x-ray and $\gamma$-ray observations are supported, with archival flux points being used for lower energy observations.
