The Fermi telescope, located in near-Earth orbit, may have detected the source of gravitational waves previously recorded by the ground-based LIGO (Laser Interferometric Gravitational Observatory) observatories. This is reported in a preprint posted on the NASA website.
The space observatory recorded a weak gamma signal 0.4 seconds after LIGO observatories detected space-time waves. Astrophysicists working for Fermi began searching for the source of gravitational waves in the electromagnetic bands an hour after the discovery of LIGO.
The gravitational observatory found out that the source of the event GW150914, associated with gravitational waves, is located in the southern hemisphere. In the same place, in the constellations of Cetus or Pisces, the Fermi telescope discovered a source of unusual gamma rays. The observatory could not determine its location more precisely.
The nature of the signal received by Fermi is best explained by the collision of two black holes, rather than the emission of magnetars, pulsars or neutron stars. Meanwhile, the statistics collected by the space telescope are not yet sufficient to declare the discovery (there is a possibility that the signal is generated by fluctuations in the atmosphere). Scientists will continue to collaborate with LIGO.
Gravitational waves were recorded on September 14, 2015 at 05:51 a.m. ET (13:51 p.m. ET) at two twin detectors of the LIGO laser interferometric gravitational wave observatory located in Livingston, Louisiana and Hanford, Washington) in the USA.
Disturbances are generated by a pair of black holes (29 and 36 times heavier than the Sun) in the last fractions of a second before they merge into a more massive rotating gravitational object (62 times heavier than the Sun). The merger of black holes happened 1.3 billion years ago (for so long the gravitational disturbance spread to the Earth).