Neutrino-induced polarization rotation in active galactic nuclei plasmas

AbstraktAbstract

We study parity-violating birefringence induced by an asymmetric neutrino background in plasmas associated with active galactic nuclei (AGN). We derive a directionality factor arising from the relative bulk motion between the neutrino medium and plasma, and show that it can produce an anomalous frequency dependence of the polarization-rotation angle, distinct from the omega-2 scaling of Faraday rotation. This anomalous scaling can occur either at the resonance plasma frequency condition omega similar or equal to omega p, or when E0 nu similar or equal to m nu omega/omega p lies within the range of the neutrino energy spectrum. We estimate the effect for three scenarios: jets propagating through the cosmic neutrino background (C nu B), jets with an internal flux of high-energy neutrinos, and accretion-disk plasma permeated by the C nu B. Of the three scenarios, the latter gives the largest rotation angle phi d similar to 10-35 rad, at x-ray frequencies. Although the predicted rotation angles are below current polarimetric sensitivity, the identified spectral signatures provide a theoretical framework for probing neutrino asymmetries and AGN plasma properties independent of magnetic field models.

We study parity-violating birefringence induced by an asymmetric neutrino background in plasmas associated with active galactic nuclei (AGN). We derive a directionality factor arising from the relative bulk motion between the neutrino medium and plasma, and show that it can produce an anomalous frequency dependence of the polarization-rotation angle, distinct from the omega-2 scaling of Faraday rotation. This anomalous scaling can occur either at the resonance plasma frequency condition omega similar or equal to omega p, or when E0 nu similar or equal to m nu omega/omega p lies within the range of the neutrino energy spectrum. We estimate the effect for three scenarios: jets propagating through the cosmic neutrino background (C nu B), jets with an internal flux of high-energy neutrinos, and accretion-disk plasma permeated by the C nu B. Of the three scenarios, the latter gives the largest rotation angle phi d similar to 10-35 rad, at x-ray frequencies. Although the predicted rotation angles are below current polarimetric sensitivity, the identified spectral signatures provide a theoretical framework for probing neutrino asymmetries and AGN plasma properties independent of magnetic field models.