Speaker
Description
The blazar B2 1420+32 (OQ 334, z = 0.682) has recently emerged as a primary laboratory for studying the "changing-look" (CL) phenomenon in jetted active galactic nuclei, characterized by transitions between FSRQ and BL Lac states. We present a detailed investigation into the complex nature of its X-ray emission using Swift-XRT observations spanning MJD 58095--60580. Using Bayesian Blocks segmentation, we identify three distinct X-ray flaring episodes (X1, X2, X3) and characterize their spectral evolution through flux-photon index hysteresis analysis. Flare X1 traces a clockwise loop, indicative of a cooling-dominated regime. Flare X2 exhibits a complex multi-loop structure reflecting its multi-peaked morphology and evolving spectral hardness. Flare X3, the brightest outburst, shows a predominantly clockwise pattern with notably harder spectral indices throughout, also consistent with cooling-dominated emission. While no flux-photon index correlation exists across the overall X-ray population, a significant moderate positive correlation emerges exclusively during the CL epochs, suggesting the X-ray emission is coupled to the jet's spectral evolution. To constrain the physical conditions driving these outbursts, we model the broadband spectral energy distributions (SEDs) of all three flaring states and the quiescent state (Q) within a single-zone leptonic framework incorporating synchrotron, SSC, and external Compton (EC) processes.