Research Fellows Directory
Dr Alberto Sesana
University of Birmingham
The existence of gravitational waves is a natural consequence of the theory of General Relativity. Their direct detection will provide invaluable information about the astrophysics of the sources and the foundations of gravity, making it one of the main goals of contemporary astrophysics and fundamental physics.
Among the loudest expected gravitational wave sources are supermassive black hole (SMBH) binaries. In fact, SMBHs are ubiquitous in galaxy centers, evolving in symbiosis with their host galaxies. When galaxy merge, the SMBHs they host sink toward the center forming a SMBH binary. In the standard hierarchical structure formation scenario, these mergers are frequent, and SMBH binaries should be fairly common. Yet, their nature is very elusive, making them among the less understood systems in our Universe.
Precise timing of an array of ultra-stable millisecond pulsars -- i.e. pulsar timing arrays (PTAs)-- is an excellent tool for the detection of gravitational waves in the nHz regime, where SMBH binaries are expected to be the loudest sources in the Universe. Preparing the ground for such a detection, and maximizing its scientific payouts is the central goal of my fellowship. Central to this goal is a deep theoretical understanding of the SMBH binary population and dynamics, which is may main scientific expertise and interest. The modeling of the dynamics of the SMBHs with their stellar and gaseous environment is crucial to guide the development of targeted data analysis pipelines and to recover useful astrophysical information from a detection or an upper limit.
Interests and expertise (Subject groups)