In the first month of the third observing run (O3) of the LIGO-Virgo detectors, five binary merger candidates have been announced. Three of them are binary black hole merger candidates, one a binary neutron star merger candidate (the first such merger, GW170817, was detected last year, which was also observed by a large number of telescopes worldwide), and the remaining one could be the highly awaited merger event of a Neutron Star and a Black Hole, which has not been observed before. The detectors have identified a relatively large area in the sky as the probable region from which the gravitational waves were emitted (Note that LIGO-India promises to dramatically reduce this localisation uncertainty). Several astronomers across the world, including groups from India, are searching this whole area painstakingly with telescopes for the electromagnetic (EM) radiation that these merger candidates would emit, though no EM counterpart has been detected so far. At this rate, many Astronomers are not going to get much sleep for a year while O3 is on!
Press Release by the LIGO and Virgo Collaborations
Several Indian researchers from different institutions are part of this exciting endeavour through the LIGO-India Scientific Collaboration (LISC).