Extreme mass ratio inspiral

Extreme mass ratio inspiral (EMRI) refers to a specific type of gravitational wave event that occurs when a small compact object, such as a stellar-mass black hole or a neutron star, orbits around a much more massive black hole, typically a supermassive black hole with a mass millions to billions of times that of the sun. The mass ratio of the two objects in an EMRI is extreme, often greater than 1000:1.