Varstrometry for Off-nucleus and Dual (sub)Kpc Active Galactic Nuclei

The mergers of binary supermassive black holes (SMBHs, that is, black holes that weigh more than one million times the mass of the Sun) in the distant Universe produce the loudest gravitational wave sirens. These gravitational waves are detectable with future space- and ground-based gravitational wave observatories. The prospects of detecting these gravitational wave sources, however, depend on the demography of binary SMBHs.

Finding close pairs of SMBHs in the distant Universe, the progenitor population of merging SMBHs, has been observationally challenging. This project will utilize a new method to efficiently search for close SMBH pairs in the distant Universe. It will quantify their abundance and study their physical properties.

This program will provide a large sample of close SMBH pairs. This sample will help us understand the formation and evolution of binary SMBHs on their journey towards final coalescence. This research project will advance the field of SMBHs.

It will also create societal values in terms of the dissemination of knowledge in classrooms and public education, as well as dedicated outreach programs to promote diversity in science.

This project aims to search for rare, close-separation pairs of SMBHs in the distant Universe following galaxy collisions. It will develop a novel method to detect the jitter in the light centroid from a pair of SMBHs. If both SMBHs are accreting matter they will produce a pair of quasars.

Due to the asynchronized random variability from both quasars in the pair, the light centroid of the (unresolved) system will display a small jitter on the sky. This jitter can be detected by precise positional measurements from the Gaia satellite. Candidates selected using Gaia data will be followed up to confirm the dual quasar nature.

This project will produce the first large sample of distant dual SMBHs at close separations. Furthermore, it will enable crucial constraints on the evolution of dual SMBHs in the distant Universe. This award addresses/advances the goals of the Windows on the Universe Big Idea.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.