The Game of Life on a Magnetar Crust: From Gamma-Ray Flares to FRBs

Abstract

This Letter presents a model to unify the diverse range of magnetar activity, through the building and release of elastic stress from the crust. A cellular automaton drives both local and global yielding of the crust, leading to braiding of coronal loops and energy release. The model behaves like a real magnetar in many ways: giant flares and small bursts both occur, as well as periods of quiescence whose typical duration is either ≲1 yr or ∼10–30 yr. The burst energy distribution broadly follows an earthquake-like power law over the energy range 10 ^40 –10 ^45 erg. The local nature of coronal loops allows for the possibility of high-energy and fast radio bursts from the same magnetar. Within this paradigm, magnetar observations can be used to constrain the poorly understood mechanical properties of the neutron-star crust.

Keywords

• Neutron stars
• X-ray bursts
• Radio bursts
• Magnetars