Equilibrium spin pulsars unite neutron star populations

Abstract

Many pulsars are formed with a binary companion from which they can accrete matter. Torque exerted by accreting matter can cause the pulsar spin to increase or decrease, and over long times, an equilibrium spin rate is achieved. Application of accretion theory to these systems provides a probe of the pulsar magnetic field. We compare the large number of recent torque measurements of accreting pulsars with a high-mass companion to the standard model for how accretion affects the pulsar spin period. We find that many long spin period (P > 100 s) pulsars must possess either extremely weak (B < 10^10 G) or extremely strong (B > 10^14 G) magnetic fields. We argue that the strong-field solution is more compelling, in which case these pulsars are near spin equilibrium. Our results provide evidence for a fundamental link between pulsars with the slowest spin periods and strong magnetic fields around high-mass companions and pulsars with the fastest spin periods and weak fields around low-mass companions. The strong magnetic fields also connect our pulsars to magnetars and strong-field isolated radio/X-ray pulsars. The strong field and old age of our sources suggests their magnetic field penetrates into the superconducting core of the neutron star.

6 pages, 4 figures; to appear in MNRAS

References in corpus (7)

• The ATNF Pulsar Catalogue
• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• A Radio Pulsar/X-ray Binary Link
• On the birthrates of Galactic neutron stars
• Spin-Down of Radio Millisecond Pulsars at Genesis
• Discovery of 47-s pulsations in the X-ray source 1RXS J225352.8+624354
• Signs of magnetic accretion in young Be/X-ray pulsar SXP 1062

Cited by in corpus (36)

• Measuring the neutron star equation of state using X-ray timing
• Approximate Universal Relations for Neutron Stars and Quark Stars
• Discovery of pulsations from NGC 300 ULX1 and its fast period evolution
• The radio telescope search for the resonant conversion of cold dark matter axions from the magnetized astrophysical sources
• The Spin Distribution of Fast Spinning Neutron Stars in Low Mass X-Ray Binaries: Evidence for Two Sub-Populations
• The Ups & Downs of Accreting X-Ray Pulsars: Decade-long observations with the Fermi Gamma-Ray Burst Monitor
• Implications of an r-mode in XTE J1751-305: Mass, radius and spin evolution
• The 2019 super-Eddington outburst of RX J0209.6-7427: Detection of pulsations and constraints on the magnetic field strength
• M51 ULX-7: super-orbital periodicity and constraints on the neutron star magnetic field
• Constraints on the symmetry energy from observational probes of the neutron star crust
• Magnetic fields of neutron stars in X-ray binaries
• Revisiting the archetypical wind accretor Vela X-1 in depth -- A case study of a well-known X-ray binary and the limits of our knowledge
• Spectral and Timing Nature of the Symbiotic X-ray Binary 4U 1954+319: The Slowest Rotating Neutron Star in an X-ray Binary System
• Ejector and propeller spin-down: How might a superluminous supernova millisecond magnetar become the 6.67 hr pulsar in RCW103
• Super-Strong Magnetic Fields of Neutron Stars in Be X-Ray Binaries Estimated with New Torque and Magnetosphere Models
• Population Synthesis of Accreting Neutron Stars Emitting Gravitational Waves
• A multi-wavelength study of SXP 1062, the long period X-ray pulsar associated with a supernova remnant
• How to make a mature accreting magnetar
• Spin equilibrium in strongly-magnetized accreting stars
• A Bayesian approach for torque modelling of BeXRB pulsars with application to super-Eddington accretors
• Accreting magnetars: linking ultraluminous X-ray pulsars and the slow pulsation X-ray pulsars
• Gravitomagnetic effect in magnetized neutron stars
• Fast flaring observed from XMMU J053108.3-690923 by eROSITA: a supergiant fast X-ray transient in the Large Magellanic Cloud
• Understanding the coexistence of spin-up and spin-down behaviors in long period X-ray pulsars
• Study on the magnetic field strength of NGC 300 ULX1
• Early neutron star evolution in high-mass X-ray binaries
• Neutron star inner crust: effects of rotation and magnetic fields
• Gravitational waves from an SMBH binary in M87
• On the Bimodal Spin Period Distribution of Be/X-ray Pulsars
• Measuring the magnetic dipole moment and magnetospheric fluctuations of SXP 18.3 with a Kalman filter
• Looking for Hall attractor in astrophysical sources
• Observational evidence for a spin-up line in the P-Pdot diagram of millisecond pulsars
• Measuring the magnetic dipole moment and magnetospheric fluctuations of accretion-powered pulsars in the Small Magellanic Cloud with an unscented Kalman filter
• The nature of the X-ray pulsar in M31: an intermediate mass X-ray binary?
• Study of recently discovered Be/X-ray pulsar MAXI J0655-013 using NuSTAR
• Studying magnetic fields of ultraluminous X-ray pulsars using different accretion torques