Blazar Flares as an Origin of High-energy Cosmic Neutrinos?

By Kohta Murase, F. Oikonomou, M. Petropoulou. Astrophysical Journal, 2018

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We consider implications of high-energy neutrino emission from blazar flares, including the recent event IceCube-170922A and the 2014–2015 neutrino flare that could originate from TXS 0506+056. First, we discuss their contribution to the diffuse neutrino intensity taking into account various observational constraints. Blazars are likely to be subdominant in the diffuse neutrino intensity at sub-PeV energies, and we show that blazar flares like those of TXS 0506+056 could make ≲1%–10% of the total neutrino intensity. We also argue that the neutrino output of blazars can be dominated by the flares in the standard leptonic scenario for their γ-ray emission, and energetic flares may still be detected with a rate of . Second, we consider multi-messenger constraints on the source modeling. We show that luminous neutrino flares should be accompanied by luminous broadband cascade emission, emerging also in X-rays and γ-rays. This implies that not only γ-ray telescopes like Fermi but also X-ray sky monitors such as Swift and MAXI are critical to test the canonical picture based on the single-zone modeling. We also suggest a two-zone model that can naturally satisfy the X-ray constraints while explaining the flaring neutrinos via either photomeson or hadronuclear processes.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/aca28b893a24c89fd6146ca8f1efb115b5e57de9