Accretion disks around supermassive black holes ( SMBHs ) in active galactic nuclei contain stars , stellar mass black holes , and other stellar remnants , which perturb the disk gas gravitationally .
The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks .
We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients , applied to two different analytic , steady-state disk models of SMBH accretion disks .
We find that there are radii in such disks where the gas torque changes sign , trapping migrating objects .
Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative , around 20–300 R _ { g } , where R _ { g } = 2 GM / c ^ { 2 } is the Schwarzschild radius .
At these traps , massive objects in the AGN disk can accumulate , collide , scatter , and accrete .
Intermediate mass black hole formation is likely in these disk locations , which may lead to preferential gap and cavity creation at these radii .
Our model thus has significant implications for SMBH growth as well as gravitational wave source populations .