Different States of a BL Lac object, OJ 287, during a flare in 2009

Blazars, which include BL Lacertae (BL Lac) and Flat Spectrum Radio Quasars (FSRQ) are compact, highly variable (from radio through TeV gamma-ray) flat spectrum radio loud active galactic nuclei (AGN) with their jet aligned close to line of sight.  Their spectral energy distribution (SED) is characterized by two broad humps. The low energy hump (radio to x-ray) is well understood as synchrotron radiation from relativistic electrons while the high-energy hump ( MeV to ~TeV) is still under debate and is supposed to be due to inverse Compton (IC) interactions. Due to their extreme variability across whole spectrum i.e from radio to gamma-ray, simultaneous multi-wavelength monitoring is essential to constrain the emission mechanism as well as their relative importance especially at high energy.
OJ 287 is a low-energy peaked blazar of BL Lac class which shows recurrent optical burst every ~11.6 years. It is modeled as a binary black hole (Kerr) system in which  the impact of secondary (1.3 x 10^8 solar mass) on the accretion of primary (1.8 x  10^10 solar mass) leads to two optical outburst per period, ~1-2 year apart along with many tidal bursts. I will discuss the quasi- simultaneous SED modeling of various states of  OJ 287 during 2009 flare (tidal) via synchrotron self Compton method using one zone leptonic model.