Description:

Massive black hole (BH) binaries and mergers are promising gravitational wave (GW) sources for pulsar timing arrays and for LISA. These highly energetic GW events could be observed out to high redshift, in the epoch where massive BH seeds are thought to form. However, much is still unknown about the BH population even in the local Universe; for example, the rates of BH binary formation, inspiral, and merger are highly uncertain. I will describe recent observational and theoretical progress in constraining the electromagnetic (EM) and GW signatures of BH pairs, binaries, and GW recoils, focusing on our results from galactic- to cosmological-scale hydrodynamics simulations. Nuclear obscuration during galaxy mergers likely plays a significant role in the elusive nature of BH pairs, and our work demonstrates that a high fraction of infrared-selected merging galaxies should contain BH pairs resolvable with JWST or with future X-ray imaging. Detections of such systems in the coming years will provide important constraints on GW event rates in advance of LISA. Finally, I’ll discuss prospects for identifying candidate recoiling BHs; such objects could provide an additional EM constraint on BH merger rates.​

Speaker: Laura Blecha, University of Florida

Host: Luke Kelly

Keywords: Physics, Astronomy, Astrophysics