@article {40033,
	title = {Blazar Flares as an Origin of High-energy Cosmic Neutrinos?},
	volume = {865},
	year = {2018},
	month = {2018/10/1},
	pages = {124},
	publisher = {IOP},
	abstract = {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 ≲ 1 {yr}}<SUP>-1</SUP>. 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.},
	keywords = {astroparticle physics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, galaxies: active, galaxies: jets, gamma rays: galaxies, High Energy Physics - Phenomenology, neutrinos, radiation mechanisms: non-thermal},
	isbn = {0004-637X},
	url = {https://ui.adsabs.harvard.edu/abs/2018ApJ...865..124M},
	author = {Murase, Kohta and Oikonomou, Foteini and Petropoulou, Maria}
}
