{
  "id": "2109.04156",
  "version": "v1",
  "published": "2021-09-09T10:33:50.000Z",
  "updated": "2021-09-09T10:33:50.000Z",
  "title": "Magnetic Field Structure and Faraday Rotation of the Plerionic Supernova Remnant G21.5$-$0.9",
  "authors": [
    "Paul C. W. Lai",
    "C. -Y. Ng",
    "Niccolo' Bucciantini"
  ],
  "comment": "9 pages, 8 figures, submitted to ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We present a polarimetric study of the pulsar wind nebula (PWN) in supernova remnant G21.5$-$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.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-09-09T10:33:50.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "plerionic supernova remnant g21",
      "magnetic field structure",
      "faraday rotation",
      "pulsar spin axis direction",
      "overall radial"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}