Constraints on Kerr-Newman black holes from merger-ringdown gravitational-wave observations

Understand

We construct a template to model the post-merger phase of a binary black hole coalescence in the presence of a remnant $U(1)$ charge.

• We include the quasi-normal modes typically dominant during a binary black hole coalescence, $(\ell,m,n) = \{(2,2,0), (2,2,1)\}$ and also present analytical fits for the quasinormal mode frequencies of a Kerr-Newman black hole in terms of its spin and charge, here also including the $(3,3,0)$ mode.
• Aside from astrophysical electric charge, our template can accommodate extensions of the Standard Model, such as a dark photon.
• Applying the model to LIGO-Virgo detections, we find that we are unable to distinguish between the charged and uncharged hypotheses from a purely post-merger analysis of the current events.