The electromagnetic afterglows of gravitational waves as a test for   Quantum Gravity
  We argue that if particularly powerful electromagnetic afterglows of the gravitational waves bursts will be observed in the future, this could be used as a strong observational support for some suggested quantum alternatives for black holes (e.g., firewalls and gravastars). A universal absence of powerful afterglows should be taken as a suggestive argument against such hypothetical quantum-gravity objects. 
M. A. Abramowicz, T. Bulik, G. F. R. Ellis, K. A. Meissner, M. Wielgus
gr-qc