Accreting Millisecond X-ray Pulsars: observational properties
Abstract
After almost two decades from the discovery of the first accreting millisecond X-ray pulsar (AMXP) SAX J1808.4-3658, the sample of accreting rapidly-rotating neutron stars harboured in low mass X-ray binary systems has increased in number up to 22 and our understanding of the millisecond pulsar population changed dramatically. The extremely short spin periods shown by the AMXPs are the result of long-lasting mass transfer from low mass companion stars through an accretion disc onto a slow-rotating NS as predicted by the so-called "recycling scenario". At the end of the mass transfer phase, a millisecond pulsar shining from the radio to the gamma-ray band, and powered by the rotation of its magnetic field, is expected to turn on. The close link shared by radio millisecond pulsars and AMXPs has been observationally confirmed by the transitional binary systems IGR J18245-2452 as well as by other transitional millisecond pulsars. Here I will review the properties of AMXPs, with particular attention to the last discoveries and to the long-term orbital and spin evolution. I will highlight what we know and what we have still to learn about in order to fully understand the (sometime puzzling) behaviour of these systems.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E1196S