Magnetic Field Structure and Faraday Rotation of the Plerionic Supernova Remnant G21.5$-$0.9
| Autor: | Lai, Paul C. W., Ng, C. -Y., Bucciantini, Niccolo' |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/ac63b1 |
| Popis: | We present a polarimetric study of the pulsar wind nebula (PWN) in supernova remnant G21.5$-$0.9 using archival Very Large Array (VLA) data. The rotation measure (RM) map of the PWN shows a symmetric pattern that aligns with the presumed pulsar spin axis direction, implying a significant contribution of RM from the nebula. We suggest that the spatial variation of the internal RM is mostly caused by non-uniform distribution of electrons originated from the supernova ejecta. Our high-resolution radio polarization map reveals an overall radial $B$-field. We construct a simple model with an overall radial $B$-field and turbulence in small scale. The model can reproduce many of the observed features of the PWN, including the polarization pattern and polarized fraction. The results also reject a large-scale toroidal $B$-field which implies that the toroidal field observed in the inner PWN cannot propagate to the entire nebula. Comment: 11 pages, 10 figures, accepted for publication in ApJ |
| Databáze: | arXiv |
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