title: A massive pulsar in a compact relativistic binary.
abstract: Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 ± 0.04 solar mass (M⊙) pulsar in a 2.46-hour orbit with a 0.172 ± 0.003 M⊙ white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn, Germany. jantoniadis@mpifr-bonn.mpg.de
authors.forename: John
authors.initials: J
authors.lastname: Antoniadis
authors.forename: Paulo C C
authors.initials: PC
authors.lastname: Freire
authors.forename: Norbert
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authors.lastname: Wex
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Tauris
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Lynch
authors.forename: Marten H
authors.initials: MH
authors.lastname: van Kerkwijk
authors.forename: Michael
authors.initials: M
authors.lastname: Kramer
authors.forename: Cees
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authors.lastname: Bassa
authors.forename: Vik S
authors.initials: VS
authors.lastname: Dhillon
authors.forename: Thomas
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authors.lastname: Driebe
authors.forename: Jason W T
authors.initials: JW
authors.lastname: Hessels
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Kaspi
authors.forename: Vladislav I
authors.initials: VI
authors.lastname: Kondratiev
authors.forename: Norbert
authors.initials: N
authors.lastname: Langer
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Marsh
authors.forename: Maura A
authors.initials: MA
authors.lastname: McLaughlin
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Pennucci
authors.forename: Scott M
authors.initials: SM
authors.lastname: Ransom
authors.forename: Ingrid H
authors.initials: IH
authors.lastname: Stairs
authors.forename: Joeri
authors.initials: J
authors.lastname: van Leeuwen
authors.forename: Joris P W
authors.initials: JP
authors.lastname: Verbiest
authors.forename: David G
authors.initials: DG
authors.lastname: Whelan