CP3 Lecture: Formation of High Eccentricity Black Hole Mergers Observable by LIGO and LISA: Results from General Relativistic N-body Dynamics

Who: Johan Samsing (Princeton)
When: Monday, June 25, 2018 at 14:15
Where: The CP³ meeting room

Gravitational waves (GWs) from binary black hole (BBH) mergers have been observed by LIGO, but how and where the BBHs formed are still major questions. Theory suggests that most BBH mergers likely form in the field as a result of isolated binary evolution and/or through complicated BH interactions in dense stellar systems. Work from the past decades also indicate that these two progenitor channels give rise to very similar GW observables, which would make it difficult to observationally distinguish them. However, I will in my talk argue why many parts of this standard picture are highly incomplete, and show that large observational differences are in fact to be expected between different BBH merger channels. In particular, from including general relativistic (GR) effects in the description of BH interactions, I will illustrate that 5%-50% of all BBH mergers in dense stellar systems will appear in LIGO and LISA with non-zero eccentricity, which is >10-100 times more than all previous groups have reported. For field binary mergers this fraction is instead 0%. These results have major implications and hint for an exciting and promising future for probing the origin and properties of BHs with GWs.