MAGNESIA · The impact of highly magnetic neutron stars in the explosive and transient Universe

The gravitational wave window is now open. It is then imperative to build quantitative models of neutron stars that use all the available tracers to constrain fundamental physics at the highest densities and magnetic fields. The most magnetic neutron stars, the magnetars, have been recently suggested to be powering a large variety of explosive and transient events. The enormous rotational power at birth, and the magnetic energy they can release via large flares, put the magnetars in the (yet) hand-wavy interpretations of gamma-ray bursts, the early phases of double neutron star mergers, super-luminous supernovae, hypernovae, fast radio bursts, and ultra-luminous X-ray sources. However, despite knowing about 30 magnetars, we are lacking a census of how many we expect within the pulsar population, nor we have robust constraints on their flaring rates. The recent discovery of transient magnetars, of magnetar-like flares from sources with measured low dipolar magnetic fields and from typical radio pulsars, clearly showed that the magnetar census in our Galaxy is largely under-estimated. This hampers our understanding not only of the pulsar and magnetar populations, but also of them as possibly related to many of Universe’s explosive events. MAGNESIA will infer a sound Magnetar Census via an innovative approach that will build the first Pulsar Population Synthesis model able to cope with constraints/limits from multi-band observations, and taking into account 3D magnetic field evolution models and flaring rates for neutron stars. Combining expertise in multi-band observations, numerical modeling, nuclear physics, and computation, MAGNESIA will solve the physics, the observational systematic errors, and the computational challenges that inhibited previous works, to finally constrain the spin period and magnetic field distribution at birth of the neutron star population.