Abstract:
BL Lacertae (BL Lac) object OJ 287 is one of the most dynamic blazars across the directly
accessible observational windows: spectral, timing, polarization and imaging. Apart from behaviors, considered
the characteristics of blazars, it exhibits peculiar timing features like quasi-periodicity in optical flux as
well as radio-detected knots position and has shown diverse transient spectral features like a new broadband
continuum dominated activity phase, Seyfert-like soft-X-ray excess, highly transient iron line absorption
feature, a thermal-like continuum-dominated optical phase, large optical polarization swings associated with
one of the timing features, etc., that are rare in blazars and contrary to currently prevailing view of BL Lacs.
Theoretical considerations, supported by existing observations invoke scenarios involving a dynamical interplay
of accretion and/or strong-gravity-induced events (tidal forces) in a binary supermassive black hole (SMBH)
scenario to impact-induced jet and only jet activities. Many of these scenarios have some definite and quite
distinctive observationally testable predictions/claims. These considerations make OJ 287 the only BL Lac to
have an activity phase with dominance related to accretion and/or accretion-perturbation-induced jet activities.
We present a brief overview of the unique spectral features and discuss the potential of these features in
exploring not only relativistic jet physics, but also issues pertaining to accretion and accretion-regulated jet
activities, i.e., the whole spectrum of issues related to the jet-accretion paradigm
