• Login
    View Item 
    •   NWU-IR Home
    • Research Output
    • Faculty of Natural and Agricultural Sciences
    • View Item
    •   NWU-IR Home
    • Research Output
    • Faculty of Natural and Agricultural Sciences
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Spectral constraints for millisecond pulsars due to general relativistic frame dragging

    Thumbnail
    View/Open
    2005Specialconstraints art_10.1007_s10509-005-7699-2eie.pdf (246.9Kb)
    Date
    2005
    Author
    Venter, C.
    De Jager, O.C.
    Metadata
    Show full item record
    Abstract
    We develop a numerical code for simulating the magnetospheres of millisecond pulsars, which are expected to have unscreened electric potentials due to the lack of magnetic pair production. We incorporate General Relativistic (GR) expressions for the electric field and charge density and include curvature radiation (CR) due to primary electrons accelerated above the stellar surface, whereas inverse Compton scattering (ICS) of thermal X-ray photons by these electrons are neglected as a second-order effect. We apply the model to PSR J0437-4715, a prime candidate for testing the GR-Electrodynamic theory, and find that the curvature radiation spectrum cuts off at energies below 15 GeV, which are well below the threshold of the H.E.S.S. telescope, whereas Classical Electrodynamics predict a much higher cutoff near 100 GeV, which should be visible for H.E.S.S., if standard assumed Classical Electrodynamics apply. GR theory also predicts a relatively narrow pulse (2φ L ∼ 0.2 phase width) centered on the magnetic axis, which sets the beaming solid angle to ∼0.5 sr per polar cap (PC) for a magnetic inclination angle of 35∘ relative to the spin axis, given an observer which sweeps close to the magnetic axis. We also find that EGRET observations above 100 MeV of this pulsar constrain the polar magnetic field strength to B pc < 4× 108 G for a pulsar radius of 10 km and moment of inertia of 1045 g cm2. The field strength constraint becomes even tighter for a larger radius and moment of inertia. Furthermore, a reanalysis of the full EGRET data set of this pulsar, assuming the predicted pulse shape and position, should lead to even tighter constraints on neutron star and GR parameters, up to the point where the GR-derived potential and polar cap current may be questioned.
    URI
    http://hdl.handle.net/10394/10480
    https://doi.org/10.1007/s10509-005-7699-2
    Collections
    • Faculty of Natural and Agricultural Sciences [4817]

    Copyright © North-West University
    Contact Us | Send Feedback
    Theme by 
    Atmire NV
     

     

    Browse

    All of NWU-IR Communities & CollectionsBy Issue DateAuthorsTitlesSubjectsAdvisor/SupervisorThesis TypeThis CollectionBy Issue DateAuthorsTitlesSubjectsAdvisor/SupervisorThesis Type

    My Account

    LoginRegister

    Copyright © North-West University
    Contact Us | Send Feedback
    Theme by 
    Atmire NV