Chiara Mingarelli is a gravitational-wave astrophysicist who is looking to understand how supermassive black holes in the centers of massive galaxies merge, and if they merge at all. She does this by predicting their nanohertz gravitational-wave signatures, which will soon be detected by pulsar timing array experiments. With pulsar timing data, she looks for both individual supermassive black holes in binary systems and for the gravitational-wave background, which should be generated by their cosmic merger history. Before joining the Center for Computational Astrophysics, Mingarelli was a Marie Curie International Outgoing Fellow at the California Institute of Technology and at the Max Planck Institute for Radio Astronomy. She completed her Ph.D. at the University of Birmingham in the United Kingdom with Alberto Vecchio.
Galaxy mergers are a standard aspect of galaxy formation and evolution, and most (likely all) large galaxies contain supermassive black holes. As part of the merging process, the supermassive black holes should in-spiral together and eventually merge, generating a background of gravitational radiation in the nanohertz to microhertz regime. An array of precisely timed pulsars spread across the sky can form a galactic-scale gravitational wave detector in the nanohertz band. I describe the current efforts to develop and extend the pulsar timing array concept, together with recent limits which have emerged from international efforts to constrain astrophysical phenomena at the heart of supermassive black hole mergers.