Gravitational Wave Astronomy: Counterpart Predictions and Searches
Gravitational waves were predicted by Albert Einstein's theory of general relativity in 1915; one hundred years later and the first direct detection of gravitational waves was made by scientists with twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA.
As these facilities begin their second observing run, with the VIRGO detector, Cascina, Italy, joining the search in 2017, more gravitational wave signals at higher sensitivity are expected. To maximise the science potential for these gravitational wave detectors the search for an electromagnetic (light) counterpart to a signal is essential. Following triggers from the LIGO consortium multiple telescopes, both ground and space based, search the sky for the tell-tale flash that could accompany such a signal. The Liverpool Telescope is engaged in the program to characterise these fleeting transients in the sky and a paper recently accepted by the Monthly Notices of the Royal Astronomical Society details the results of their latest search here.
Understanding what these counterparts could look like is work of theorists like the ARI's Prof. Shiho Kobayashi and Ph.D student Gavin Lamb. In their recent work published in the Astrophysical Journal (link to article) they describe one potential new counterpart to the gravitational wave signal from the merger of binary neutron stars or a neutron star and a black hole. This work was recently presented by Gavin Lamb at the International Astronomy Union Symposium on the new frontiers in black hole astrophysics held in Ljubljana. A brief outline can be found in the proceedings here, and the presentation slides here.