The Michigan Gravitational Wave Group (MGWG) carries out research using the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of facilities in Hanford, Washington and Livingston, Louisiana, funded by the National Science Foundation. These observatories host 4-km-long Michelson interferometers designed to detect truly minute ripples (smaller than 1 part in 1021) of space itself, caused by violent astrophysical processes far away in our own galaxy or in distant galaxies.
On September 14, 2015, gravitational wave signals were detected
simultaneously at the LIGO Hanford and Livingston Observatories,
signals produced by the merger of two massive black holes about
1.3 billion years ago (~60 solar masses in total).
This groundbreaking discovery was both the first direct detection of gravitational waves and the first observation of binary black hole systems. The discovery was announced and published in Physical Review Letters on February 11, 2016.
|On December 26, 2015, gravitational wave signals were definitively detected for the second time, this time from black holes of ~20 solar masses in total. This detection was announced and published in Physical Review Letters on June 15, 2016.||
Third Definitive Detection -- GW170104
Searching in the Advanced LIGO data from September 2015 onward for continuous gravitational waves emitted by rapidly spinning neutron stars in our galaxy. K. Riles is Co-Chair of the LIGO Scientific Collaboration's Continuous Waves Search Group. The MGWG has developed two powerful analysis programs for carrying out all-sky searches for unknown neutron stars -- PowerFlux (dissertation work by V. Dergachev) for isolated neutron stars and TwoSpect (dissertation work by E. Goetz) for binary neutron stars.
Commissioning and detector characterization of the Advanced LIGO interferometers, which are designed to improve upon initial LIGO strain amplitude sensitivity by more than an order of magnitude. The first data run of the Advanced LIGO detectors completed in January 2016, achieving more than a factor of three improvement in strain sensitivity; it may take several more years to reach design sensitivity over the full bandwidth of interest.