Netting the wave
After its publication in 2016, it was rapidly acknowledged as the scientific breakthrough of the year, and the three researchers who did more than anyone to make it possible – Rainer Weiss, Barry Barish and Kip Thorne – received this year’s Nobel Prize in Physics: On September 14th 2015, they and the large team of international collaborators involved in the Laser Interferometer Gravitational-Wave Observatory (LIGO) had detected, for the first time, the long sought gravitational waves predicted by Einstein’s theory of general relativity. The waves whose passage was registered by LIGO on that occasion were emitted when two black holes had collided around 1.3 billion years ago.
All three confirmed detections since then have also involved collisions between black holes. Now the LIGO team has reported the detection of gravitational waves from a different type of source. And this time, the Dark Energy Survey – another international astrophysical collaboration, in which LMU researchers including Professors Joseph Mohr and Jochen Weller of the LMU Observatory play a prominent role – has succeeded in photographing the source’s optical counterpart with its own special camera, the DECam. This burst of gravitational waves was produced by the fusion of two extremely dense neutron stars about 130 million years ago, i.e. the event took place in a relatively nearby galaxy. The data show the resulting explosion (indicated by the arrow in the picture on the left). By combining the data collected by LIGO and DES with those obtained by other research consortia, it should be possible to refine the current estimate of the value of the Hubble constant, which describes the present rate of expansion of the Universe. That in turn may help the DES team to determine the nature of dark energy, the mysterious force that is thought to be responsible for accelerating the speed of cosmic expansion. Images: Dark Energy Survey
See Fermilab's press release