Ring-down gravitational waves and lensing observables: How far can a wormhole mimic those of a black hole?

Abstract

It has been argued that the recently detected ring-down gravity waveforms could be indicative only of the presence of light rings in a horizonless object, such as a surgical Schwarzschild wormhole, with the frequencies differing drastically from those of the horizon quasinormal mode frequencies ω QNM at late times. While the possibility of such a horizonless alternative is novel by itself, we show by the example of Ellis-Bronnikov wormhole that the differences in ω QNM in the eikonal limit (large l) need not be drastic. This result will be reached by exploiting the connection between ω QNM and the Bozza strong field lensing parameters. We shall also show that the lensing observables of the EllisBronnikov wormhole can also be very close to those of a black hole (say, SgrA * hosted by our galaxy) of the same mass. This situation indicates that the ringdown frequencies and lensing observables of the Ellis-Bronnikov wormhole can remarkably mimic those of a black hole. The constraint on wormhole parameter γ imposed by experimental accuracy is briefly discussed. We also provide independent arguments supporting the stability of the Ellis-Bronnikov wormhole proven recently.---------------

Strong field lensing by Damour-Solodukhin wormhole

“…A fundamental theoretical distinction between a black hole and a wormhole is that while the former possesses event horizon, the latter does not. Despite this distinction, it is found that many strong field features previously thought of as indicative of a black hole event horizon (e.g., ring-down quasi-normal modes) can be remarkably mimicked by a static wormhole [3][4][5][6][7].…”

Testing the nature of dark compact objects: a status report

“…To exclude ECO models, one needs calculations of their vibration spectra. These are available for a wide class of objects, including boson stars [86,134,517], gravastars [145,147,258], wormholes [520,521], or other quantum-corrected objects [168,172]. A major challenge in these tests is how to model spin effects properly, since few spinning ECO models are available and the study of their perturbations is much more involved than for Kerr BHs.…”

Tests for the existence of black holes through gravitational wave echoes

“…Thus, precise measurements of the ringdown frequencies and damping times allow one to test whether or not the object is a BH [174,175]. Such tests are in principle feasible for wide classes of objects, including boson stars [80,87,175], gravastars [95,97,139], wormholes [176,177], or other quantum-corrected objects [121,125].…”