Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder
2016 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 456, no 1, L84-L88 p.Article in journal (Refereed) PublishedText
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(-10.6)(+9.8) 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)degrees.
Place, publisher, year, edition, pages
Oxford University Press, 2016. Vol. 456, no 1, L84-L88 p.
instrumentation: polarimeters, techniques: polarimetric, stars: neutron, pulsars: individual: the Crab pulsar
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-182840DOI: 10.1093/mnrasl/slv177ISI: 000368010000018ScopusID: 2-s2.0-84959175886OAI: oai:DiVA.org:kth-182840DiVA: diva2:906617
QC 201602242016-02-242016-02-232016-02-24Bibliographically approved