Pulsar Timing Arrays: A New Window on the Gravitational Wave Universe (Manne Siegbahn memorial lecture 2026)

by Prof. Maura McLaughlin (West Virginia University)

Tuesday 20 Oct 2026, 15:15 → 16:15 Europe/Stockholm

Oskar Klein Auditorium

Millisecond pulsars are rapidly rotating neutron stars with phenomenal rotational stability. Pulsar timing arrays around the world monitor more than 100 of these cosmic clocks to search for perturbations caused by gravitational waves at nanohertz frequencies. The tell-tale signature of a gravitational-wave background in pulsar timing data is the presence of quadrupolar spatial correlations among pulsars across the sky. Pulsar timing array collaborations have now found evidence for these correlations in multiple independent datasets. The signal is consistent with that expected from an ensemble of supermassive black hole binaries, but could also arise from more exotic sources, such as cosmic strings or processes in the early Universe. I will describe these experiments and their most recent results, and discuss the dramatic increases in sensitivity, and the new discoveries we expect, as we combine observations from new and existing telescopes across the globe.