Revealing the Emitting Region and Variation Mechanism of PKS 1510-089

The variation mechanism of blazars is a difficult topic in the field of active galactic nucleus (AGN) studies. In this work, we collected long-term multiwavelength light curves, and utilized the local cross-correlation function to reveal their correlations. A baseline-subtraction procedure was applied to the radio data, which evidently enhanced its correlation with the γ rays to exceed the 3 σ significance level. Based on the time delays, we inferred that the γ -ray and optical bands likely share the same emission region, while the radio emission region is downstream of them at a distance of 16 pc. At the optical band, we found that the target shows a trend transition from “redder-when-brighter” (RWB) in the low-flux state to “bluer-when-brighter” (BWB) in the high-flux state. The optical and γ -ray flux correlation indicates that the external Compton process dominates the γ -ray emission. The broadband spectral energy distribution (SED) modeling for three epochs explains the RWB phenomenon, and demonstrates that the target is a typical low-synchrotron-peaked blazar. The shift of the peak frequency could comprehensively explain the spectral variation, the flux correlation, and the time-resolved SED in a consistent manner. Therefore, the variation mechanism of PKS 1510-089 is most probably due to the intrinsic particle acceleration via the shock, magnetic reconnection, or turbulence in the jet.