At the heart of many, if not all, giant galaxies lies a supermassive black hole. While “outstanding” mass black holes are 10-50 times the mass of our Sun, supermassive black holes are millions and billions of times the mass of our Sun (like the one in the film Interstellar)! Active stellar nuclei (AGN) are promising environments for the assembly of combining binary black hole (BBH) systems. We draw on simulations of BBH systems in AGN to propose a phenomenological model for the circulation of black hole spins of combining binaries in AGN disks. If the bulk of combining black holes are put together in AGNs, future gravitational-wave observations may provide insights into the dynamics of AGN disks.
At the heart of the majority of, if not all, huge galaxies lies a supermassive great void. As matter rotates around and falls into the black hole, it discharges effective radiation. Credit: ESA/Hubble (M. Kornmesser).
While “stellar” mass black holes are 10-50 times the mass of our Sun, supermassive black holes are millions and billions of times the mass of our Sun (like the one in the movie Interstellar)! Supermassive black holes (SMBH) are so big that they handle to– quite actually– end up being the centers of their galaxies.
Figure 1– Artist: Avi Vajpeyi.
The spiraling gas is understood as an accretion disk, and these can be really thick and even hide some of the celestial bodies inside. Gravitational waves from the mergers of these bodies help spill the beans: they pass through the gassy curtain and let us study both the accretion disk and merging bodies!
Researchers have been simulating bodies inside accretion disks to understand how many mergers can take place inside these disks and what the orientations of the bodies are before merging. Based upon these simulations, we have actually built a “model” to study the accretion disks age and density (ie, if the disk is dilute or thick) from the gravitational waves shot off from the mergers! A graph of the model remains in Figure 2.
Figure 2. Artist: Avi Vajpeyi.
Active stellar nuclei (AGN) are promising environments for the assembly of combining binary great void (BBH) systems. Interest in AGNs as nurseries for merging BBH is rising following the detection of gravitational waves from a BBH system from the purported pair-instability mass space, most especially, GW190521. Active stellar nuclei have also been conjured up to explain the development of the high-mass-ratio system, GW190814.
We draw on simulations of BBH systems in AGN to propose a phenomenological design for the distribution of black hole spins of combining binaries in AGN disks. If the majority of combining black holes are put together in AGNs, future gravitational-wave observations might supply insights into the dynamics of AGN disks.
Written by OzGrav researcher Avi Vajpeyi, Monash University.
