Can quasars, triggered by mergers, account for NANOGrav’s stochastic gravitational wave background?
Á. Kis-Tóth, Z. Haiman, Z. Frei, Classical and Quantum Gravity 42 (2025).

Electromagnetic signatures of supermassive black hole binaries resolved by PTAs
T.L. Tanaka, Z. Haiman, Classical and Quantum Gravity 30 (2013).

Identifying decaying supermassive black hole binaries from their variable electromagnetic emission
Z. Haiman, B. Kocsis, K. Menou, Z. Lippai, Z. Frei, Classical and Quantum Gravity 26 (2009).