1998/09/09 by Matthew G. Baring, A. K. Harding, Alice K. Harding · 8 citations
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astronomy #Astrophysics #Dipole #Geophysics and Sensor Technology #High-pressure geophysics and materials #Magnetar #Magnetic field #Magnetosphere #Neutron star #Nuclear physics #Pair production #Physics #Population #Pulsar #Pulsars and Gravitational Waves Research #Quantum mechanics #X-ray pulsar #astro-ph
paper · pdf · doi:10.1086/311679
4 pages, including one figure and one table, in AASTeX emulatapj format, Astrophysical Journal Letters, in press
arxiv created 1998/09/09 · openalex publication_date 1998/11/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The notable absence of radio pulsars having measured magnetic dipole surface field strengths above B 0 ~3 × 10 13 G naturally raises the question of whether this forms an upper limit to pulsar magnetization. Recently there has been increasing evidence that neutron stars possessing higher dipole spin-down fields do in fact exist, including a growing list of anomalous X-ray pulsars (AXPs) with long periods and spinning down with high-period derivatives, which imply surface fields of 10 14 -10 15 G. Furthermore, the recently reported X-ray period and period derivative for the soft gamma-ray repeater (SGR) source SGR 1806-20 suggest a surface field around 10 15 G. None of these high-field pulsars have yet been detected as radio pulsars. We propose that high-field pulsars should be radio quiet because electron-positron pair production in their magnetospheres, thought to be essential for radio emission, is efficiently suppressed in ultrastrong fields ( B 0 ≳4 × 10 13 G) by the action of photon splitting, a quantum electrodynamical process in which a photon splits into two. Our computed radio quiescence boundary in the radio pulsar P - diagram, where photon splitting overtakes pair creation, is located just above the boundary of the known radio pulsar population, neatly dividing them from the AXPs. We thus identify a physical mechanism that defines a new class of high-field radio-quiet neutron stars that should be detectable by their pulsed emission at X-ray and perhaps gamma-ray energies.