Gravitational-wave astronomy is an emerging branch of observational astronomy which aims to use gravitational waves (minute distortions of spacetime predicted by Einstein’s theory of general relativity) to collect observational data about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.
GW170104 was a gravitational wave signal detected by the LIGO observatory in 2017. In 2017 the LIGO and Virgo collaborations announced that they had reliably verified the signal, making it the third such signal, after GW150914 and GW151226.
The signal was detected by LIGO with the Hanford detector picking it up 3 milliseconds before the Livingston detector. The gravitational wave frequency at peak GW strain was 160 to 199 Hz.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool.
Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry.
The Indian space-based ASTROSAT mission did a related sensitive search for short duration x-ray flashes associated with the event and did not detect any.
The Italy-based VIRGO detector is almost in place and will join in to collect data later this year. The study had a major Indian contribution and the LIGO-India facility which is making immense progress will join the club in 2024.
The initial LIGO observatories were funded by the National Science Foundation (NSF) and were conceived, built, and are operated by Caltech and MIT. They collected data from 2002 to 2010 but no gravitational waves were detected. LIGO is the largest and most ambitious project ever funded by the NSF.