Predicted multi-wavelength flux and neutrino flux of TXS 0506+056 for the proton synchrotron model. The red circles are the observed multi-wavelength data and the green circle is the detected neutrino flux from the IceCube observation. The black dashed curves represent the synchrotron emission and the SSC emission, respectively (from left to right). The blue dashed curves represent the proton synchrotron emission, the synchrotron emission from the secondary pairs, and the |$\gamma$|-ray emission from |$\pi ^{0}$| decay, respectively (from left to right). The cyan dashed curves represent the synchrotron emission of the secondary pairs from the Bethe–Heitler process. The green dashed curve represents the muon neutrino spectrum from the charged pion decay. The all-flavor neutrino spectrum is also shown as the green solid curve. The red solid curve is the total spectrum from all emission components, while the red dashed curve is the EBL-corrected spectrum using the EBL model of Finke, Razzaque, and Dermer (2010). For comparison, The EBL-corrected spectrum using the EBL model of Franceschini, Rodighiero, and Vaccari (2008) is also shown as the red dotted curve. The observed data are taken from IceCube Collaboration (2018b). (Color online)