Discovering the interior of black holes
Abstract
The detection of gravitational waves (GWs) from black hole (BH) mergers provides an inroad toward probing the interior of astrophysical BHs. The generalrelativistic description of the BH interior is that of empty spacetime with a (possibly) singular core. Recently, however, the hypothesis that the BH interior does not exist has been gaining traction, as it provides a means for resolving the BH informationloss problem. Here, we propose a simple method for answering the following question: Does the BH interior exist and, if so, does it contain some distribution of matter or is it mostly empty? Our proposal is premised on the idea that, similar to the case of relativistic, ultracompact stars, any BHlike object whose interior has some matter distribution should support fluid modes in addition to the conventional spacetime modes. In particular, the Coriolisinduced Rossby (r) modes, whose spectrum is mostly insensitive to the composition of the interior matter, should be a universal feature of such BHlike objects. In fact, the frequency and damping time of these modes are determined by only the object's mass and speed of rotation. The rmodes oscillate at a lower frequency, decay at a slower rate, and produce weaker GWs than do the spacetime modes. Hence, they imprint a modelinsensitive signature of a nonempty interior in the GW spectrum resulting from a BH merger. We find that future GW detectors, such as Advanced LIGO with its design sensitivity, have the potential of detecting such rmodes if the amount of GWs leaking out quantum mechanically from the interior of a BHlike object is sufficiently large.
 Publication:

Physical Review D
 Pub Date:
 December 2017
 DOI:
 10.1103/PhysRevD.96.124021
 arXiv:
 arXiv:1701.07444
 Bibcode:
 2017PhRvD..96l4021B
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  High Energy Astrophysical Phenomena;
 High Energy Physics  Theory
 EPrint:
 Added author, added discussion of detectability, clarified conclusions, 32 pages, 3 figures. V3 agrees with the accepted version  minor revisions