Possible correlation between unabsorbed hard x rays and neutrinos in radio-loud and radio-quiet active galactic nuclei
Emma Kun, I. Bartos, J. Becker Tjus, Peter L. Biermann, A. Franckowiak, F. Halzen, S. del Palacio, Jooyun Woo
Abstract
The first high-energy neutrino source identified by IceCube was a blazar---an active galactic nucleus driving a relativistic jet toward Earth. Jets driven by accreting black holes are commonly assumed to be needed for high-energy neutrino production. Recently, IceCube discovered neutrinos from Seyfert galaxies, which appears unrelated to jet activity. Here, we show that the observed luminosity ratios of neutrinos and hard x rays from blazars $\mathrm{TXS}0506+056$ and $\mathrm{GB}6\mathrm{J}1542+6129$ are consistent with neutrino production in a $\ensuremath{\gamma}$-obscured region near a central supermassive black hole, with the x-ray flux corresponding to reprocessed $\ensuremath{\gamma}$-ray emission with flux comparable to that of neutrinos. Similar neutrino--hard x-ray flux ratios are found for four Seyfert galaxies, NGC 1068, NGC 4151, CGCG 420-015, and NGC 3079, raising the possibility of a common neutrino production mechanism that may not involve a strong jet.