Synchrotron self-Compton emission from the Crab and other pulsars

Journal Article · Sun Sep 20 04:00:00 UTC 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/811/1/63· OSTI ID:22882553

Harding, Alice K.; Kalapotharakos, Constantinos ^[1]

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1. Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

Results of a simulation of synchrotron self-Compton (SSC) emission from a rotation-powered pulsar are presented. The radiating particles are assumed to be both accelerated primary electrons and a spectrum of electron–positron pairs produced in cascades near the polar cap. They follow trajectories in a slot gap using 3D force-free magnetic field geometry, gaining pitch angles through resonant cyclotron absorption of radio photons, radiating and scattering synchrotron emission at high altitudes out to and beyond the light cylinder. Full angular dependence of the synchrotron photon density is simulated in the scattering and all processes are treated in the inertial observer frame. Spectra for the Crab and Vela pulsars as well as two energetic millisecond pulsars, B1821–24 and B1937+21, are simulated using this model. The simulation of the Crab pulsar radiation can reproduce both the flux level and the shape of the observed optical to hard X-ray emission assuming a pair multiplicity of M{sub +}=3×10{sup 5}, as well as the very-high-energy emission above 50 GeV detected by MAGIC and VERITAS, with both the synchrotron and SSC components reflecting the shape of the pair spectrum. Simulations of Vela, B1821−24, and B1937+21, for M{sub +} up to 10{sup 5}, do not produce pair SSC emission that is detectable by current telescopes, indicating that only Crab-like pulsars produce significant SSC components. The pair synchrotron emission matches the observed X-ray spectrum of the millisecond pulsars, and the predicted peak of this emission at 1–10 MeV would be detectable with planned Compton telescopes.

• OSTI ID: 22882553
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 811; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
COMPUTERIZED SIMULATION
CRAB NEBULA
ELECTRON-POSITRON INTERACTIONS
EMISSION
FORCE-FREE MAGNETIC FIELDS
GAMMA RADIATION
GEV RANGE 10-100
HARD X RADIATION
INCLINATION
MEV RANGE 01-10
NEUTRON STARS
PAIR PRODUCTION
PULSARS
RELATIVISTIC RANGE
ROTATION
SYNCHROTRON RADIATION
TELESCOPES
X-RAY SPECTRA