{
  "id": "1505.07608",
  "version": "v1",
  "published": "2015-05-28T09:16:58.000Z",
  "updated": "2015-05-28T09:16:58.000Z",
  "title": "Gamma-ray activity of Seyfert galaxies and constraints on hot accretion flows",
  "authors": [
    "Rafal Wojaczynski",
    "Andrzej Niedzwiecki",
    "Fu-Guo Xie",
    "Michal Szanecki"
  ],
  "comment": "12 pages, 5 figures, submitted to A&A",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We check how the Fermi/LAT data constrain physics of hot accretion flows, most likely present in low-luminosity AGNs. Using a precise model of emission from hot flows, we examine the dependence of their gamma-ray emission, resulting from proton-proton interactions, on accretion rate, black hole spin, magnetic field strength, electron heating efficiency and particle distribution. Then, we compare the hadronic gamma-ray luminosities predicted by the model for several nearby Seyfert 1 galaxies with the results of our analysis of 6.4 years of the Fermi/LAT observations of these AGNs. In agreement with previous studies, we find a significant gamma-ray detection in NGC 6814 and we could only derive upper limits for the remaining objects, although we note marginally significant (~3 sigma) signals at the positions of NGC 4151 and NGC 4258. The derived upper limits for the flux above 1 GeV allow us to constrain the proton acceleration efficiency in flows with heating of electrons dominated by Coulomb interactions, which case is favored by X-ray spectral properties. In such flows, at most ~10% of the accretion power can be used for a relativistic acceleration of protons. Upper limits for the flux below 1 GeV can constrain the magnetic field strength and black hole spin value, we find such constraints for NGC 7213 and NGC 4151. We also note that the spectral component above ~4 GeV found in the Fermi/LAT data of Centaurus A by Sahakyan et al. may be due to hadronic emission from a flow within the above constraint. We rule out such an origin of the gamma-ray emission from NGC 6814. Finally, we note that the three Seyfert 2/starburst galaxies, NGC 4595, NGC 1068 and Circinus, show an interesting correlation of their gamma-ray luminosities with properties of their active nuclei, and we discuss it in the context of the hot flow model.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-05-28T09:16:58.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hot accretion flows",
      "gamma-ray activity",
      "seyfert galaxies",
      "upper limits",
      "constraint"
    ],
    "publication": {
      "doi": "10.1051/0004-6361/201526621"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1373499
    }
  }
}