Published February 24, 2023 | Version Published
Journal Article

Nonlinearities in Black Hole Ringdowns

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Columbia University
  • 3. ROR icon University of Mississippi
  • 4. ROR icon Cornell University
  • 5. ROR icon Max Planck Institute for Gravitational Physics

Abstract

The gravitational wave strain emitted by a perturbed black hole (BH) ringing down is typically modeled analytically using first-order BH perturbation theory. In this Letter we show that second-order effects are necessary for modeling ringdowns from BH merger simulations. Focusing on the strain's (ℓ,m)=(4,4) angular harmonic, we show the presence of a quadratic effect across a range of binary BH mass ratios that agrees with theoretical expectations. We find that the quadratic (4,4) mode amplitude exhibits quadratic scaling with the fundamental (2,2) mode -- its parent mode. The nonlinear mode's amplitude is comparable to or even larger than that of the linear (4,4) modes. Therefore correctly modeling ringdown -- improving mismatches by an order of magnitude -- requires the inclusion of nonlinear effects.

Additional Information

We thank Max Isi and the Flatiron Institute for fostering discourse, and Vishal Baibhav, Emanuele Berti, Mark Cheung, Matt Giesler, Scott Hughes, and Max Isi for valuable conversations. Computations for this work were performed with the Wheeler cluster at Caltech. This work was supported in part by the Sherman Fairchild Foundation and by NSF Grants No. PHY-2011961, No. PHY-2011968, and No. OAC-1931266 at Caltech, as well as NSF Grants No. PHY-1912081, No. PHY-2207342, and No. OAC-1931280 at Cornell. The work of L. C. S. was partially supported by NSF CAREER Grant No. PHY-2047382. M. L. was funded by the Innovative Theoretical Cosmology Fellowship at Columbia University. L. H. was funded by the DOE DE-SC0011941 and a Simons Fellowship in Theoretical Physics. M. L. and L. C. S. thank the Benasque Science Center and the organizers of the 2022 workshop "New frontiers in strong gravity," where some of this work was performed; and M. L. acknowledges NSF Grant No. PHY-1759835 for supporting travel to this workshop.

Additional details

Identifiers

Eprint ID
119484
Resolver ID
CaltechAUTHORS:20230223-726432000.5

Funding

Sherman Fairchild Foundation
NSF
PHY-2011961
NSF
PHY-2011968
NSF
OAC-1931266
NSF
PHY-1912081
NSF
PHY-2207342
NSF
OAC-1931280
NSF
PHY-2047382
Columbia University
Department of Energy (DOE)
DE-SC0011941
Simons Foundation
NSF
PHY-1759835

Dates

Created
2023-02-23
Created from EPrint's datestamp field
Updated
2023-02-23
Created from EPrint's last_modified field

Caltech Custom Metadata