Millisecond pulsars are the fastest-spinning compact stars in the universe. They are prime targets for probing the strong interaction at supranuclear densities and  searching for continuous gravitational wave sources. A long-standing paradigm assumes that a millisecond pulsar in a binary system can be powered either by the rotation of the pulsar's magnetic field or by the accretion of plasma from a companion star during its evolution. However, the discovery of optical and UV pulsations from a pair of millisecond pulsars has recently challenged this standard scenario. The high optical pulsed luminosity cannot be explained by emission mechanisms commonly operating in binary pulsars, such as accretion-powered emission. The coherent variability observed at optical and X-ray energies suggests that the acceleration of charged particles to extremely high speeds can occur in the magnetosphere of a neutron star, even when it is engulfed in accreting matter. I will review the state of the art of binary millisecond pulsars from an observational perspective, showing the multi- wavelength signatures appearing during the accretion and quiescent states.

Breve CV della Dr.ssa Arianna Miraval Zanon:

Arianna Miraval Zanon studia millisecond pulsars in sistemi binari a diverse lunghezze d'onda, dai raggi-X alle onde radio. Ha conseguito la sua Laurea Magistrale in Astronomia all'Università di Padovanel 2017, completando la sua tesi all'Osservatorio di Cagliari, dove studiò le radio pulsar. Dopo aver ottenuto il suo dottorato all'Università dell'Insubria nel 2021, ha iniziato la sua carriera di ricerca all'Osservatorio Astronomico di Roma. Dal 20233, ricopre la posizione di tecnologo all'Agenzia Spaziale Italiana.