Multiwavelength photometric and spectroscopic monitoring of changing-look blazar B2 1420+32

Blazars are active galactic nuclei with their relativistic jets pointing directly to observers. We inspected the multi-wavelength temporal and spectral variability of the blazar, B2 1420+32. Multi-epoch spectra show that the blazar exhibited large scale spectral variability in both its continuum and line emission, accompanied by dramatic gamma-ray and optical variability up to factors of 40 and 15, respectively, over week to month timescales and of several hundreds over years timescale. B2 1420+32 was an FSRQ with a blue continuum and broad emission lines in 1995 and transited between BL Lac and FSRQ states multiple times following a series of flares starting in 2018. We observed an emergence of a strong pseudo Fe continuum as well as single-temperature black body components of 11,000 and 5,400 K in two spectra. These “changing look” features, collectively, have never been observed previously in blazars. The large Fe continuum flux increase and blackbody flux suggest the occurrence of dust sublimation releasing more Fe ions in the central engine and an energy transfer from relativistic jet to sub-relativistic emission in thermal shocks or line emission respectively, probing the possibility of a new AGN feedback channel which will provide insight into understanding black hole-galaxy co-evolution.