2019ApJ...883..137P

PKS 1510-089 is one of the most variable blazars in the third Fermi-LAT source catalog. During 2015, this source has shown four flares identified as flares A, B, C, and D in between three quiescent states: Q1, Q2, and Q3. The multiwavelength data from Fermi-LAT, Swift-XRT/Ultraviolet/Optical Telescope, Owens Valley Radio Observatory, and Sub-millimeter array Observatory are used in our work to model these states. Different flux doubling times have been observed in different energy bands, which indicate that there could be multiple emission zones. The flux doubling time from the gamma-ray and X-ray light curves are found to be 10.6 hr, 2.5 days, and the average flux doubling time in the optical/UV band is 1 day. It is possible that the gamma-ray and optical/UV emission are produced in the same region whereas X-ray emission is coming from a different region along the jet axis. We have also estimated the discrete correlation functions (DCFs) among the light curves of different energy bands to infer about their emission regions. However, our DCF analysis does not show significant correlation in different energy bands though it shows peaks in some cases at small time lags. We perform a two-zone multiwavelength time-dependent modeling with one emission zone located near the outer edge of the broad line region and another further away in the dusty/molecular torus (DT/MT) region to study this high state.