Echoes of Kerr-like wormholes

Abstract

Structure at the horizon scale of black holes would give rise to echoes of the gravitational wave signal associated with the post-merger ringdown phase in binary coalescences. We study the waveform of echoes in static and stationary, traversable wormholes in which perturbations are governed by a symmetric effective potential. We argue that echoes are dominated by the wormhole quasinormal frequency nearest to the fundamental black hole frequency that controls the primary signal. We put forward an accurate method to construct the echoes waveform(s) from the primary signal and the quasinormal frequencies of the wormhole, which we characterize. We illustrate this in the static Damour-Solodukhin wormhole and in a new, rotating generalization that approximates a Kerr black hole outside the throat. Rotation gives rise to a potential with an intermediate plateau region that breaks the degeneracy of the quasinormal frequencies. Rotation also leads to late-time instabilities which, however, fade away for small angular momentum.

Quantum Black Holes in the Sky

“…There are two natural frequencies for the waveform of the echoes: The resonance frequencies (natural harmonics) of the echo chamber (formed by the angular momentum barrier and the near-horizon quantum structure), and the BH ringdown (or classical QNM) frequencies. The high frequency harmonics that are initially excited by the merger event decay quickly, while the low frequency harmonics live for longer time [146][147][148]. While the former captures the repeat period of the echoes, the latter describes the echo internal structure.…”

Observational signatures of wormholes with thin accretion disks

“…al. in [53] and the second is the rotating version of the Morris-Thorne wormhole, also known as the Teo wormhole [54]. We construct accretion disk images for these wormholes numerically.…”

Analytical model for gravitational-wave echoes from spinning remnants

“…Furthermore, using an accurate template is crucial for model selection and to discriminate the origin of the echoes in case of a detection. There has been a considerable progress in modeling the echo waveform [20,[25][26][27][28][29][30][31], but the approaches adopted so far are not optimal, since they are either based on analytical templates not necessarily related to the physical properties of the remnant, or rely on model-dependent numerical waveforms which are inconvenient for matched filtered searches and can be computationally expensive. In this paper, we provide an analytical, physically motivated template that is parametrized by the standard ringdown parameters plus two physical quantities related to the properties of the exotic remnant.…”