VERITAS detection of VHE emission from the optically bright quasar OJ 287

Understand

We report on the VERITAS detection of very-high-energy (VHE, $E > 100~\mathrm{GeV}$) $\gamma$-ray emission from the optically bright quasar OJ 287 which is located at a redshift of z = 0.306.

• OJ 287 has been observed to display regular optical outbursts with a period of approximately 12 years, with the last major optical outburst having occurred in 2015.
• To explain this periodicity, models involving a binary supermassive black hole system at the core of OJ 287, or a helical jet, have been developed.
• Motivated by elevated Swift-XRT count rates, VERITAS observed OJ 287 in February 2017, and detected the object at >5 standard deviations above background.