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ARE THE TWO BLACK HOLES OBSERVED BY LIGO PRODUCED FROM THE COLLAPSE OF A SINGLE STAR?

Image: Simulation of two colliding black holes. Animation created by SXS, the Simulating eXtreme Spacetimes (SXS) project (http://www.black-holes.org) - Caltech LIGO

If the GW signal observed by LIGO is due to the merger of two isolated black holes (BHs) in vacuum, no electromagnetic counterparts are expected. However, Fermi observed a signal 0.4 s after LIGO in a region of space compatible with the GW source.



A recent paper (Loeb 2016) suggests that the two black holes could be the result of the collapse of a single massive and rapidly rotating star. In this scenario the GRB is produced from a jet generated in the accretion disk of residual debris around the black hole or from an outflow generating by the BHs' merging.

The detection of a GRB afterglow in the future could be used to determine the precise localization of the electromagnetic source and eventually confirm the association to the GW source.

  • Loeb 2016 (accepted for publication in ApJ Letters) - Electromagnetic Counterparts to Black Hole Mergers Detected by LIGO (arXiv)




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