A correlation between hard X-rays and neutrinos in radio-loud and radio-quiet AGN
Emma Kun, Imre Bartos, Julia Becker Tjus, Peter L. Biermann, Anna Franckowiak, Francis Halzen, Santiago del Palacio, Jooyun Woo
arXiv:2404.06867v1 Announce Type: new
Abstract: The production mechanism of astrophysical high-energy neutrinos is not yet understood. A common assumption is that beamed relativistic outflows (jets) driven by accreting black holes are needed to accelerate particles to such high energies to produce high-energy neutrinos. Indeed, the first astrophysical high-energy neutrino source candidate identified by IceCube at a significance level of $>3sigma$ was a blazar — an AGN with an accreting supermassive black hole that drives a relativistic jet directed towards Earth. Recently, IceCube discovered strong evidence that Seyfert galaxies also emit neutrinos, which appears unrelated to jet activity. Here, we show that the neutrino–hard X-ray flux ratio of the blazar TXS 0506+056 is consistent with neutrino production in a $gamma$-obscured region near the central supermassive black hole, with the X-ray flux corresponding to reprocessed $gamma$-ray emission with flux comparable to that of neutrinos. Similar neutrino–hard X-ray flux ratios were found for three of IceCube’s Seyfert galaxies, raising the possibility of a common neutrino production mechanism that may not involve a strong jet. We examine how future observations could test the jet origin of blazar neutrinos.arXiv:2404.06867v1 Announce Type: new
Abstract: The production mechanism of astrophysical high-energy neutrinos is not yet understood. A common assumption is that beamed relativistic outflows (jets) driven by accreting black holes are needed to accelerate particles to such high energies to produce high-energy neutrinos. Indeed, the first astrophysical high-energy neutrino source candidate identified by IceCube at a significance level of $>3sigma$ was a blazar — an AGN with an accreting supermassive black hole that drives a relativistic jet directed towards Earth. Recently, IceCube discovered strong evidence that Seyfert galaxies also emit neutrinos, which appears unrelated to jet activity. Here, we show that the neutrino–hard X-ray flux ratio of the blazar TXS 0506+056 is consistent with neutrino production in a $gamma$-obscured region near the central supermassive black hole, with the X-ray flux corresponding to reprocessed $gamma$-ray emission with flux comparable to that of neutrinos. Similar neutrino–hard X-ray flux ratios were found for three of IceCube’s Seyfert galaxies, raising the possibility of a common neutrino production mechanism that may not involve a strong jet. We examine how future observations could test the jet origin of blazar neutrinos.