For the second time scientists from LIGO observed gravitational wave – ripples in the fabric of spacetime. Two scientists from the Astronomical Observatory have contributed to this discovery.


During the conference in San Diego group of researchers from LIGO Scientific Collaboration (LSC) and Virgo Collaboration presented the data of twin Laser Interferometer Gravitational-Wave Observatory detectors, located in Livingston and Hanford. The observations lasted from 12th September to 19th January 2016.


In February gravitational waves were detected for the first time in  history. They were produced during the final fraction of a second of the merger of two black holes that  produced a single, more massive spinning black hole (GW150914). On 26th December LIGO detectors observed gravitational waves for the second time. This time they were produced as a consequence of a merger of two black holes – 14 and 8 times the mass of the sun (GW151226). The collision of two black holes lead to formation of  a single, more massive, spinning black hole – with the mass 21 times the mass of the sun.


Observations confirm that binary black holes are quite common in the Universe.  Signal shape of these three objects agrees perfectly  with predictions of Albert Einstein’s general theory of relativity.


Scientists from POLGRAW group (which is a part of Virgo Collaboration) were involved in the second detection of the gravitational waves. Among them were Professor Tomasz Bulik and Doctor Izabela Kowalska-Leszczyńska from the University of Warsaw. Professor Bulik with Professor Belczyński, also a University of Warsaw scholar,  were involved in simulations of binaries that showed that binary black holes are the most likely objects to be detected by LIGO. Prof. Bulik was a co-editor of one chapter of the discovery paper. Doctor Kowalska-Leszczyńska was carrying out research on astrophysical characteristics of binary black holes as well as characterization of the detector noise.


Scientists from the UW, together with 7 researchers from POLGRAW group and other physicist sans, are among the authors of the second discovery of gravitational waves.


It is  predicted that the detections of gravitational waves will be more common very soon. – In the near future, Virgo, the European interferometer, will join a growing network of gravitational wave detectors, which work together with ground-based telescopes that follow-up on the signals – notes Fulvio Ricci, the Virgo Collaboration spokesperson. – The three interferometers together will permit a far better localization in the sky of the signals – he adds.


LIGO’s next data-taking run will begin in the autumn. By then, further improvements in detector sensitivity are expected to allow LIGO to reach as much as 1.5 to 2 times more of the volume of the universe. The Virgo detector is expected to join in the latter half of the upcoming observing run.