Just a thought: gravitational waves from quasar accretion disks?? (Patreon)

It's been a productive few weeks for some of the research teams I'm working with. This paper just came out on the archive (again, not yet accepted by the journal!) It's an idea a few of us had not long after the first detection of a gravitational wave by LIGO last year. Those merging black holes just seemed too massive to have formed from regular stellar remnants. A couple of my collaborators (Barry & Saavik, the first two lead authors) have been thinking about what would happen to a black hole that ended up in the accretion disk of a quasar. Turns out they grow very quickly and can get stuck for a while in "migration traps" before finding their way to the central supermassive black hole. What better place to collect, grow, and merge multiple black holes? That led us wonder if the LIGO events came from exactly this type of merger. This paper does a first pretty crude look at the expected frequency of such events. The hardest part of this was understanding how black holes might migrate and merge in the accretion disk, which I had no part in! My work was in the initial wild speculation, and then helping to figure out how stellar-mass black holes "rain down" on the central quasar from the larger galaxy to give a veritable black hole swarm to feed the accretion disk (Section 4). That's a crazy thought all by itself. 

https://arxiv.org/abs/1702.07818