12:00–1:00 pm ERC 401
Luke Kelley (Northwestern University) "Binary Massive Black Holes, Active Galactic Nuclei, and Gravitational Waves"
Black holes are the brightest, most massive, and most energetic sources in the Universe. Massive black holes (MBHs) are also believed to shape the fate of entire galaxies, although the mechanism of either this 'feedback' or their formation, remains a mystery. Following galaxy mergers, pairs of MBHs can form binaries which produce low-frequency gravitational waves (GWs) that will soon be detectable by pulsar timing arrays, like NANOGrav. I have developed the most advanced and comprehensive simulations available for studying MBH binaries, their host galaxy interactions, and the GWs they produce. I will describe my predictions for both GW and electromagnetic signatures, and highlight the unique discovery space opened up by multimessenger (GW + electromagnetic) astrophysics. Excitingly, we may soon be able to test these predictions for the first time: within the NANOGrav collaboration we recently identified a nanohertz signal that is consistent with low-frequency GWs. As the chair of NANOGrav's astrophysics working group, I am leading the development of a comprehensive framework for predicting and interpreting the upcoming GW and electromagnetic signatures. In a separate effort, we are developing a new generation of cosmological simulations to model the high-redshift MBHs that will soon be observable with JWST, and eventually with the space-based LISA mission. I will highlight how my research program will leverage these detections to finally reveal how MBHs form in the early Universe and co-evolve with galaxies over cosmic time.
