A recent change in the optical and gamma-ray polarization of the Crab nebula and pulsar

作者：Moran P; Kyne G; Gouiffes C^*; Laurent P; Hallinan G; Redfern R M; Shearer A^*

来源：Monthly Notices of the Royal Astronomical Society, 2016, 456(3): 2974-2981.

DOI：10.1093/mnras/stv2780

• polarization
• radiation mechanisms: non-thermal
• stars: neutron
• pulsars: individual: the Crab pulsar

We report on observations of the polarization of optical and gamma-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope, Advanced Camera for Surveys and the International Gamma-Ray Astrophysics Laboratory satellite (INTEGRAL). These, when combined with other optical polarization observations, suggest that the polarized optical emission and gamma-ray polarization changes in a similar manner. A change in the optical polarization angle has been observed by this work, from 109.5 +/- 0.degrees 7 in 2005 to 85.3 +/- 1.degrees 4 in 2012. On the other hand, the gamma-ray polarization angle changed from 115 +/- 11 degrees in 2003-2007 to 80 +/- 12 degrees in 2012-2014. Strong flaring activities have been detected in the Crab nebula over the past few years by the high-energy gamma-ray missions Agile and Fermi, and magnetic reconnection processes have been suggested to explain these observations. The change in the polarized optical and gamma-ray emission of the Crab nebula/pulsar as observed, for the first time, by GASP and INTEGRAL may indicate that reconnection is possibly at work in the Crab nebula. We also report, for the first time, a non-zero measure of the optical circular polarization from the Crab pulsar+knot system.

• 出版日期2016-3-1
• 单位中国地震局