LIGO-Virgo finds mystery astronomical object in 'mass gap'

(Northwestern University) Scientists from the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the European Virgo observatory, including Northwestern University astronomers, have detected a mystery object inside the puzzling area known as the "mass gap" -- the range that lies between the heaviest known neutron star and the lightest known black hole. The intriguing object of 2.6 solar masses was found on Aug. 14, 2019, as it merged with a black hole of 23 solar masses, generating a ...