{
  "id": "2107.09063",
  "version": "v1",
  "published": "2021-07-19T18:00:00.000Z",
  "updated": "2021-07-19T18:00:00.000Z",
  "title": "Extragalactic magnetism with SOFIA (Legacy Program) -- II: The bimodal magnetic field in the starburst ring of NGC 1097",
  "authors": [
    "Enrique Lopez-Rodriguez",
    "Rainer Beck",
    "Susan E. Clark",
    "Annie Hughes",
    "Alejandro S. Borlaff",
    "Eva Ntormousi",
    "Lucas Grosset",
    "Konstantinos Tassis",
    "John E. Beckman",
    "Kandaswamy Subramanian",
    "Daniel Dale",
    "Tanio Diaz-Santos",
    "Legacy Team"
  ],
  "comment": "15 pages, 9 figures, Submitted to ApJ",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present the properties of the magnetic field (B-field) in the starburst ring of the galaxy NGC 1097. Thermal polarized emission at 89 $\\mu$m using HAWC+/SOFIA shows that the polarized flux is spatially located at the contact regions of the outer-bar with the starburst ring. The linear polarization decomposition analysis shows that the $89$ $\\mu$m and radio ($3.5$ and $6.2$ cm) polarization traces two different modes, $m$, of the B-field: a constant B-field orientation and dominated by $m=0$ at $89$ $\\mu$m, and a spiral B-field dominated by $m=2$ at radio. The $^{12}CO(2-1)$ integrated emission line peaks in the inner $\\sim0.69$ kpc, the FIR polarized flux peaks in the central $\\sim 1.02$ kpc, and the radio polarized flux peaks in the outer $\\sim1.39$ kpc of the starburst ring. Dust temperature is higher, $T_{89\\mu m} = 30.7\\pm0.4$ K, at the region of the FIR polarized flux than at the radio's region, $T_{3.5cm} = 26.2\\pm1.7$ K. We argue that the B-field at 89 $\\mu$m is concentrated in the warmest region of a shock front caused by the galactic density wave in the contact regions between the outer-bar with the starburst ring. Radio polarization traces a superposition of the spiral B-field outside and within the starburst ring. According to Faraday rotation measures between $3.5$ and $6.2$ cm, the radial component of the B-field along the contact regions points toward the galaxy's center on both sides. Gas streams follow the B-field, which feeds the black hole with matter from the host galaxy.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-07-19T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "starburst ring",
      "bimodal magnetic field",
      "extragalactic magnetism",
      "legacy program",
      "contact regions"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 15,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}