Magnetars

International audienceWhat is the origin of neutron star magnetic fields ? Although the fossil field hypothesis (i.e. the amplification of the neutron star progenitor field by flux conservation) would be the simplest mechanism, it seems unlikely to explain the existence of magnetars, which are a peculiar type of neutron stars endowed with unusually strong dipolar magnetic fields. Their intensity is currently deduced from stellar spin-down rate measurements and estimated to be in the order of $10^{15}$ Gauss, which makes them the strongest magnetic fields ever observed in the Universe. Understanding the formation process of magnetars is of particular importance, since they are believed to power a variety of outstanding explosive events observed with ongoing and future transient surveys (LSST, SVOM)