<?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%">Keivani, A.</style></author><author><style face="normal" font="default" size="100%">Murase, K.</style></author><author><style face="normal" font="default" size="100%">Petropoulou, M.</style></author><author><style face="normal" font="default" size="100%">Fox, D. B.</style></author><author><style face="normal" font="default" size="100%">Cenko, S. B.</style></author><author><style face="normal" font="default" size="100%">Chaty, S.</style></author><author><style face="normal" font="default" size="100%">Coleiro, A.</style></author><author><style face="normal" font="default" size="100%">Delaunay, J. J.</style></author><author><style face="normal" font="default" size="100%">Dimitrakoudis, S.</style></author><author><style face="normal" font="default" size="100%">Evans, P. A.</style></author><author><style face="normal" font="default" size="100%">Kennea, J. A.</style></author><author><style face="normal" font="default" size="100%">Marshall, F. E.</style></author><author><style face="normal" font="default" size="100%">Mastichiadis, A.</style></author><author><style face="normal" font="default" size="100%">Osborne, J. P.</style></author><author><style face="normal" font="default" size="100%">Santander, M.</style></author><author><style face="normal" font="default" size="100%">Tohuvavohu, A.</style></author><author><style face="normal" font="default" size="100%">Turley, C. F.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications for High-energy Neutrino Emission and Cosmic-Ray Acceleration</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%">Astrophysics - High Energy Astrophysical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">BL Lacertae objects: general</style></keyword><keyword><style  face="normal" font="default" size="100%">BL Lacertae objects: individual: TXS 0506+056</style></keyword><keyword><style  face="normal" font="default" size="100%">galaxies: active</style></keyword><keyword><style  face="normal" font="default" size="100%">gamma rays: galaxies</style></keyword><keyword><style  face="normal" font="default" size="100%">neutrinos</style></keyword><keyword><style  face="normal" font="default" size="100%">radiation mechanisms: non-thermal</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2018/09/1</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://ui.adsabs.harvard.edu/abs/2018ApJ...864...84K</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">IOP</style></publisher><volume><style face="normal" font="default" size="100%">864</style></volume><pages><style face="normal" font="default" size="100%">84</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%">Detection of the IceCube-170922A neutrino coincident with the flaring blazar TXS 0506+056, the first and only ∼3σ high-energy neutrino source association to date, offers a potential breakthrough in our understanding of high-energy cosmic particles and blazar physics. We present a comprehensive analysis of TXS 0506+056 during its flaring state, using newly collected Swift, NuSTAR, and X-shooter data with Fermi observations and numerical models to constrain the blazar’s particle acceleration processes and multimessenger (electromagnetic (EM) and high-energy neutrino) emissions. Accounting properly for EM cascades in the emission region, we find a physically consistent picture only within a hybrid leptonic scenario, with γ-rays produced by external inverse-Compton processes and high-energy neutrinos via a radiatively subdominant hadronic component. We derive robust constraints on the blazar’s neutrino and cosmic-ray emissions and demonstrate that, because of cascade effects, the 0.1-100 keV emissions of TXS 0506+056 serve as a better probe of its hadronic acceleration and high-energy neutrino production processes than its GeV-TeV emissions. If the IceCube neutrino association holds, physical conditions in the TXS 0506+056 jet must be close to optimal for high-energy neutrino production, and are not favorable for ultrahigh-energy cosmic-ray acceleration. Alternatively, the challenges we identify in generating a significant rate of IceCube neutrino detections from TXS 0506+056 may disfavor single-zone models, in which γ-rays and high-energy neutrinos are produced in a single emission region. In concert with continued operations of the high-energy neutrino observatories, we advocate regular X-ray monitoring of TXS 0506+056 and other blazars in order to test single-zone blazar emission models, clarify the nature and extent of their hadronic acceleration processes, and carry out the most sensitive possible search for additional multimessenger sources.</style></abstract></record></records></xml>