Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder

M. Chauvin, H. G. Florén, M. Jackson, T. Kamae, T. Kawano, M. Kiss, M. Kole, V. Mikhalev, E. Moretti, G. Olofsson, S. Rydström, H. Takahashi, A. Iyudin, M. Arimoto, Y. Fukazawa, J. Kataoka, N. Kawai, T. Mizuno, F. Ryde, H. TajimaT. Takahashi, M. Pearce*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    20 Citations (Scopus)


    We have measured the linear polarization of hard X-ray emission from the Crab in a previously unexplored energy interval, 20-120 keV. The introduction of two new observational parameters, the polarization fraction and angle stands to disentangle geometrical and physical effects, thereby providing information on the pulsar wind geometry and magnetic field environment. Measurements are conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter. Polarization is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an anticoincidence well. The polarimetric response has been characterized prior to flight using both polarized and unpolarized calibration sources. We address possible systematic effects through observations of a background field. The measured polarization fraction for the integrated Crab light curve is 18.4+9.8 -10.6 per cent, corresponding to an upper limit (99 per cent credibility) of 42.4 per cent, for a polarization angle of (149.2 ± 16.0)°.

    Original languageEnglish
    Pages (from-to)L84-L88
    JournalMonthly Notices of the Royal Astronomical Society: Letters
    Issue number1
    Publication statusPublished - 2016 Feb 11


    • Instrumentation: polarimeters
    • Pulsars: individual: the crab pulsar
    • Stars: neutron
    • Techniques: polarimetric

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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