{
  "id": "2211.01737",
  "version": "v1",
  "published": "2022-11-03T12:03:57.000Z",
  "updated": "2022-11-03T12:03:57.000Z",
  "title": "Selected results from IceCube",
  "authors": [
    "Teresa Montaruli"
  ],
  "comment": "12 pages, 7 figures",
  "journal": "Proceedings of CRIS 2022 Conference",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Neutrino astronomy saw its birth with the discovery by IceCube of a diffuse flux at energies above 60 TeV with intensity comparable to a predicted upper limit to the flux from extra-galactic sources of ultra-high energy cosmic rays (UHECRs). While such an upper limit corresponds to the case of calorimetric sources, in which cosmic rays lose all their energy into photo-pion production, the first statistically significant coincident observation between neutrinos and gamma rays was observed from a blazar of intriguing nature. A very-high-energy muon event, of most probable neutrino energy of 290 TeV for an $E^{-2.13}$ spectrum, alerted other observatories triggering a large number of investigations in many bands of the electromagnetic (EM) spectrum. A high gamma-ray state from the blazar was revealed soon after the event and in a follow-up to about 40 days. A posteriori observations also in the optical and radio bands indicated a rise of the flux from the TXS 0506+056 blazar. A previous excess of events of the duration of more than 100~d was observed by IceCube with higher significance than the alert itself. These observations triggered more complex modeling than simple one-zone proton synchrotron models for proton acceleration in jets of active galactic nuclei (AGNs) and more observations across the EM spectrum. A second piece of evidence was a steady excess of about 50 neutrino events with reconstructed soft spectrum in a sample of lower energy well-reconstructed muon events than the alert event. A hot spot was identified in a catalog of 110 gamma-ray intense emitters and starburst galaxies in a direction compatible with NGC 1068 with a significance of $2.9\\sigma$. NGC 1068 hosts a mildly relativistic jet in a starburst galaxy, seen not from the jet direction but rather through the torus. This Seyfert II galaxy is at only 14.4~Mpc from the Earth. We discuss these observations.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-11-03T12:03:57.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "selected results",
      "simple one-zone proton synchrotron models",
      "ultra-high energy cosmic rays",
      "starburst galaxy",
      "first statistically significant coincident observation"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}