Magnetars and Fundamental QED Physics in the MeV Band

Prof. Matthew G. Baring

Rice University

Magnetars are among the most powerful compact objects in the stellar mass range observed in the Milky Way. Periodicity seen in magnetar quiescent and outburst emission, and distinctive "spin-down" lengthening of the period have driven the paradigm that neutron stars with magnetic fields exceeding 100 TeraGauss constitute these fascinating sources. This talk highlights observational elements and theoretical signatures in the sub-MeV waveband of dissipative processes in magnetar magnetospheres, including Comptonization and associated polarization. In particular it discusses the potential action of exotic QED mechanisms of photon splitting and magnetic pair creation and their imprint on magnetar spectra. The prospect of an observational vindication of these predictions of fundamental physics by a sensitive MeV-band telescope like AMEGO is addressed, including enhanced diagnostics afforded by polarimetric capability.