title: A radio pulsar/x-ray binary link.
abstract: Radio pulsars with millisecond spin periods are thought to have been spun up by the transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no radio pulsations have been detected. Here we report on detection and follow-up observations of a nearby radio millisecond pulsar (MSP) in a circular binary orbit with an optically identified companion star. Optical observations indicate that an accretion disk was present in this system within the past decade. Our optical data show no evidence that one exists today, suggesting that the radio MSP has turned on after a recent LMXB phase.
authors.affiliation: Department of Physics, McGill University, 3600 Rue University, Montréal, Quebec, H3A 2T8, Canada. aarchiba@physics.mcgill.ca
authors.forename: Anne M
authors.initials: AM
authors.lastname: Archibald
authors.forename: Ingrid H
authors.initials: IH
authors.lastname: Stairs
authors.forename: Scott M
authors.initials: SM
authors.lastname: Ransom
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Kaspi
authors.forename: Vladislav I
authors.initials: VI
authors.lastname: Kondratiev
authors.forename: Duncan R
authors.initials: DR
authors.lastname: Lorimer
authors.forename: Maura A
authors.initials: MA
authors.lastname: McLaughlin
authors.forename: Jason
authors.initials: J
authors.lastname: Boyles
authors.forename: Jason W T
authors.initials: JW
authors.lastname: Hessels
authors.forename: Ryan
authors.initials: R
authors.lastname: Lynch
authors.forename: Joeri
authors.initials: J
authors.lastname: van Leeuwen
authors.forename: Mallory S E
authors.initials: MS
authors.lastname: Roberts
authors.forename: Frederick
authors.initials: F
authors.lastname: Jenet
authors.forename: David J
authors.initials: DJ
authors.lastname: Champion
authors.forename: Rachel
authors.initials: R
authors.lastname: Rosen
authors.forename: Brad N
authors.initials: BN
authors.lastname: Barlow
authors.forename: Bart H
authors.initials: BH
authors.lastname: Dunlap
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Remillard