<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Xue, Rui</style></author><author><style face="normal" font="default" size="100%">Liu, Ruo-Yu</style></author><author><style face="normal" font="default" size="100%">Petropoulou, Maria</style></author><author><style face="normal" font="default" size="100%">Oikonomou, Foteini</style></author><author><style face="normal" font="default" size="100%">Wang, Ze-Rui</style></author><author><style face="normal" font="default" size="100%">Wang, Kai</style></author><author><style face="normal" font="default" size="100%">Wang, Xiang-Yu</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A Two-zone Model for Blazar Emission: Implications for TXS 0506+056 and the Neutrino Event IceCube-170922A</style></title><short-title><style face="normal" font="default" size="100%">The Astrophysical Journal</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">1100</style></keyword><keyword><style  face="normal" font="default" size="100%">164</style></keyword><keyword><style  face="normal" font="default" size="100%">633</style></keyword><keyword><style  face="normal" font="default" size="100%">731</style></keyword><keyword><style  face="normal" font="default" size="100%">739</style></keyword><keyword><style  face="normal" font="default" size="100%">Astrophysics - High Energy Astrophysical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Blazars</style></keyword><keyword><style  face="normal" font="default" size="100%">Gamma-ray sources</style></keyword><keyword><style  face="normal" font="default" size="100%">High energy astrophysics</style></keyword><keyword><style  face="normal" font="default" size="100%">High-energy cosmic radiation</style></keyword><keyword><style  face="normal" font="default" size="100%">Neutrino astronomy</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2019/11/1</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://ui.adsabs.harvard.edu/abs/2019ApJ...886...23X</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">IOP</style></publisher><volume><style face="normal" font="default" size="100%">886</style></volume><pages><style face="normal" font="default" size="100%">23</style></pages><isbn><style face="normal" font="default" size="100%">0004-637X</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A high-energy muon neutrino event, IceCube-170922A, was recently discovered in both spatial and temporal coincidence with a gamma-ray flare of the blazar TXS 0506+056. It has been shown with standard one-zone models that neutrinos can be produced in the blazar jet via hadronic interactions, but with a flux that is mostly limited by the X-ray data. In this work, we explore the neutrino production from TXS 0506+056 by invoking two physically distinct emission zones in the jet, with an inner blob inside of or close to the broad-line region (BLR) and an outer one well beyond the BLR. Using the Doppler-boosted radiation of the BLR as the target photon field, the inner zone accounts for the neutrino and gamma-ray emission via pγ interactions and inverse Compton scattering, respectively, while the outer zone produces the optical and X-ray emission via synchrotron and synchrotron self-Compton processes. The different conditions of the two zones allow us to suppress the X-ray emission from the electromagnetic cascade, and set a much higher upper limit on the muon neutrino flux (i.e., ∼10&lt;SUP&gt;-11&lt;/SUP&gt; erg cm&lt;SUP&gt;-2&lt;/SUP&gt; s&lt;SUP&gt;-1&lt;/SUP&gt;) than in one-zone models. We compare our scenario in detail with one-zone models discussed in the literature, and argue that differentiating between such scenarios will become possible with next-generation neutrino telescopes, such as IceCube-Gen2.</style></abstract></record></records></xml>