Are the magnetic fields of millisecond pulsars ~ 10^8 G?

Abstract

It is generally assumed that the magnetic fields of millisecond pulsars (MSPs) are $\sim 10^8$G. We argue that this may not be true and the fields may be appreciably greater. We present six evidences for this: (1) The $\sim 10^8$ G field estimate is based on magnetic dipole emission losses which is shown to be questionable; (2) The MSPs in low mass X-ray binaries (LMXBs) are claimed to have $<10^{11}$ G on the basis of a Rayleygh-Taylor instability accretion argument. We show that the accretion argument is questionable and the upper limit $10^{11}$ G may be much higher; (3) Low magnetic field neutron stars have difficulty being produced in LMXBs; (4) MSPs may still be accreting indicating a much higher magnetic field; (5) The data that predict $\sim 10^8$ G for MSPs also predict ages on the order of, and greater than, ten billion years, which is much greater than normal pulsars. If the predicted ages are wrong, most likely the predicted $\sim 10^8$ G fields of MSPs are wrong; (6) When magnetic fields are measured directly with cyclotron lines in X-ray binaries, fields $\gg 10^8$ G are indicated. Other scenarios should be investigated. One such scenario is the following. Over 85% of MSPs are confirmed members of a binary. It is possible that all MSPs are in large separation binaries having magnetic fields $>10^8$ G with their magnetic dipole emission being balanced by low level accretion from their companions.

arXiv comment16 pages, accept for publication in Astrophysics and Space Science

References in corpus (18)

• The ATNF Pulsar Catalogue
• Sonic-Point Model of Kilohertz Quasi-Periodic Brightness Oscillations in Low-Mass X-ray Binaries
• Magnetic Fields of Accreting X-Ray Pulsars with the Rossi X-Ray Timing Explorer
• The Disk-Magnetosphere Interaction in the Accretion-Powered Millisecond Pulsar SAX J1808.4-3658
• Global Three-Dimensional Simulations of Black Hole Accretion Disks: X-ray Flares in the Plunging Region
• Millisecond Pulsar Velocities
• The Orbit of X Per and Its Neutron Star Companion
• On the Dramatic Spin-up/Spin-down Torque Reversals in Accreting Pulsars
• The 0.1-100 keV Spectrum of LMC X-4 in the High State: Evidence for a High Energy Cyclotron Absorption Line
• The birth properties of Galactic millisecond radio pulsars
• Evidence against field decay proportional to accreted mass in neutron stars
• Warped Disks as a Possible Origin of Torque Reversals in Accretion-Powered Pulsars
• Magnetically Driven Precession of Warped Disks and Milli-Hertz Variabilities in Accreting X-Ray Pulsars
• A BeppoSAX observation of Her X-1 during the first main-on after an anomalous low-state: evidence for rapid spin-down
• The Steady Spin Down Rate of 4U 1907+09
• Is there evidence for field restructuring or decay in accreting magnetic white dwarfs?
• The Connection Between Low-Mass X-ray Binaries and (Millisecond) Pulsars: A Binary Evolution Perspective
• Production and evolution of millisecond X-ray and radio pulsars