Speaker
Description
Blazars exhibit a characteristic double-humped, non-thermal spectral energy distribution and polarized emission from radio through X-ray energies. While spectral modeling constrains the physical conditions within the emitting region, it does not uniquely constrain the underlying magnetic-field geometry. Polarization provides an additional diagnostic that is sensitive to the projected magnetic-field structure and radiative geometry of the jet.
We present an angle-dependent, polarization-sensitive one-zone leptonic blazar model that consistently calculates the linear Stokes parameters of synchrotron and synchrotron self-Compton (SSC) emission. We investigate the polarization signatures produced by ordered poloidal, toroidal, and helical magnetic-field configurations as a function of their orientation relative to the line of sight.
Our calculations reveal a strong dependence of the synchrotron and SSC polarization signatures on magnetic-field and viewing geometry. In particular, configurations that produce similar or weakly varying synchrotron polarization can exhibit substantially different SSC polarization signatures, demonstrating that SSC polarization can retain information about the underlying magnetic-field structure that is not readily apparent from the synchrotron component alone. For helical magnetic fields, the polarization can also vary non-monotonically with viewing angle due to changes in the projected field structure and the resulting cancellation of Stokes contributions across the emission region. These results highlight the diagnostic potential of broadband polarimetry for constraining magnetic-field structures in blazar jets and provide a theoretical framework for interpreting current and future X-ray and high-energy polarization observations.