TY - JOUR
T1 - The PoGO+ view on Crab off-pulse hard X-ray polarization
AU - Chauvin, M.
AU - Florén, H. G.
AU - Friis, M.
AU - Jackson, M.
AU - Kamae, T.
AU - Kataoka, J.
AU - Kawano, T.
AU - Kiss, M.
AU - Mikhalev, V.
AU - Mizuno, T.
AU - Tajima, H.
AU - Takahashi, H.
AU - Uchida, N.
AU - Pearce, M.
N1 - Funding Information:
We are grateful to S. Vadawale and the AstroSat CZTI Collaboration for generously making their data available to us and for valuable discussions. This research was supported by The Swedish National Space Board, The Knut and Alice Wallenberg Foundation, The Swedish Research Council, The Japan Society for Promotion of Science, and ISAS/JAXA.
Publisher Copyright:
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
PY - 2018/6/1
Y1 - 2018/6/1
N2 - The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.
AB - The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.
KW - Instrumentation: polarimeters
KW - Methods: statistical
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U2 - 10.1093/mnrasl/sly027
DO - 10.1093/mnrasl/sly027
M3 - Article
AN - SCOPUS:85102921472
SN - 1745-3933
VL - 477
SP - L45-L49
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
IS - 1
ER -