High-energy Photon Opacity in the Twisted Magnetospheres of Magnetars

Abstract Magnetars are neutron stars characterized by strong surface magnetic fields generally exceeding the quantum critical value of 44.1 TG. High-energy photons propagating in their magnetospheres can be attenuated QED processes like photon splitting and pair creation. In this paper, we compute opacities due to creation emitted anywhere magnetosphere a magnetar. Axisymmetric, twisted dipole field configurations embedded Schwarzschild metric treated. The paper computes maximum energies for transparency that permit propagation infinity curved spacetime. Special emphasis is given cases where generated along loops and/or polar regions; these directly relate resonant inverse Compton scattering models hard X-ray emission from magnetars Comptonized soft gamma-ray giant flares. We find increases magnetospheric twists raise or lower opacities, depending on both locale competition between field-line straightening strength enhancement. Consequently, implicit spectral bursts persistent “tail” magnetars, considerations constrain region locales twist angle magnetosphere; constraints probed future telescopes such as COSI AMEGO. inclusion opaque volume above its threshold, except when regions approximately parallel field.