Radio and optical light curves of the blazar J1549+0237 with a spatially associated neutrino, IC160924A. Top panel (A) shows the radio (OVRO) light curve. Middle panel (B) shows the optical (CAZ) light curve. Bottom panel (C) shows the optical (CAZ) light curve when converted into observational blocks (see Sect. 3.1.2). The solid vertical (magenta) line shows the moment of neutrino arrival. In case of radio, the time window for AI calculation is 2.3 years (see Sect. 3), shown by dotted vertical lines. In optical, the observational block used for AI calculation is within ±30 days of the neutrino arrival (see gray shading). For this association, the AI values in radio and optical are 1.74 and 0.688, respectively.