Speaker
Description
Gravitational waves at nanohertz frequencies offer a unique view of the universe on its largest scales, probing supermassive black hole binary populations, galaxy evolution, and potentially exotic cosmological processes. Pulsar timing arrays detect these waves by monitoring the arrival times of radio pulses from ensembles of millisecond pulsars with extraordinary precision over years to decades. Multiple international collaborations have now confirmed a stochastic gravitational wave background in their data, opening an entirely new branch of astronomy. Moving beyond detection toward characterizing the spectrum and resolving individual sources of this signal requires more pulsars, better sensitivity, and longer baselines. The gamma ray pulsar timing array adds a complementary and independent pathway, leveraging pulsars across the full sky with a fundamentally different set of instrumental and astrophysical systematics. My group at ASTRON is leading this science at the frontier, advancing detection techniques and sensitivity analysis across both radio and gamma ray datasets. In this talk, I will present the current state of the art in nanohertz gravitational wave detection, discuss how next generation radio facilities will transform our ability to grow pulsar ensembles and resolve individual sources, and argue that upgrades to the Westerbork Synthesis Radio Telescope can play a critical role in these efforts.