Photon‐splitting Cascades in Gamma‐Ray Pulsars and the Spectrum of PSR 1509−58
Citations Over TimeTop 10% of 1997 papers
Abstract
Magnetic photon splitting, a QED process that becomes important only in magnetic fields approaching the quantum critical value, B_cr = 4.41 X 10^13 Gauss, is investigated as a mechanism for attenuation of gamma-rays emitted near the surface of strongly-magnetized pulsars. We model photon splitting attenuation and subsequent splitting cascades in gamma-ray pulsars, including the dipole field and curved spacetime geometry of the neutron star magnetosphere. We focus specifically on PSR1509-58, which has the highest surface magnetic field of all the gamma-ray pulsars (B_0 = 3 X 10^13 Gauss). We find that splitting will not be important for most gamma-ray pulsars, i.e. those with B_0 ~ 0.3 B_cr, where the splitting attenuation lengths and escape energies become comparable to or less than those for pair production. We compute Monte Carlo spectral models for PSR1509-58. We find that photon splitting, or combined splitting and pair production, can explain the unusually low cutoff energy (between 2 and 30 MeV) of PSR1509-58, and that the model cascade spectra, which display strong polarization, are consistent with the observed spectral points and upper limits for polar cap emission at a range of magnetic colatitudes up to ~ 25 degrees.
Related Papers
- Handbook of Pulsar Astronomy(2004)
- → Selection of radio pulsar candidates using artificial neural networks(2010)122 cited
- → The Parkes multibeam pulsar survey - IV. Discovery of 180 pulsars and parameters for 281 previously known pulsars(2004)184 cited
- Pulsars as physics laboratories(1993)
- → Pulsar interpulses and other off-pulse emission(1977)4 cited