© 2019, Accademia Nazionale dei Lincei. We present updated observations of the blazar PG 1553+113, a bright BL Lac Object that yields quasi-periodic gamma-ray emission every 2.2 years, strongly suggesting the activity of a super-massive binary black hole. Such binary systems are widely held to emit low-frequency gravitational waves. Confirming the binary nature of PG 1553+113 is very relevant for upcoming searches of nHz gravitational waves.
|Publication status||Published - 1 Jan 2019|
- Active galactic nuclei
- Gamma rays