University physicists were among a group of scientists at the Laser Interferometer Gravitational-wave Observatory who observed and detected a collision between two dead neutron stars 130 million light years away, according to a University press release. This is the first time a cosmic event has been observed using both gravitational waves and light.
The collision occurred 130 million years ago, but was seen and detected for the first time Aug. 17 using the LIGO Livingston Observatory, the LIGO Hanford Observatory in Hanford, Washington and the Virgo interferometer in Italy. As the stars spiraled toward each other, they gave off gravitational waves which could be detected for about 100 seconds early on Aug. 17. The collision resulted in an explosion of gamma rays, which could be seen on earth for about two seconds. Other forms of light were detected in the following weeks according to the press release.
LSU Department of Physics & Astronomy professor and former LIGO Scientific Collaboration spokesperson Gabriela González said in the press release the observation is a landmark for astronomers around the world.
“This first observation of gravitational waves caused by two neutron stars colliding is not only a breakthrough for the LIGO-Virgo Scientific Collaboration that detected this, but also for our colleagues who study neutron stars, gamma-ray flashes and other astronomical phenomena,” González said.
The combination of gravitational waves detection and the measurement of gamma rays makes the observation the first to confirm Einstein’s general theory of relativity, which predicts that gravitational waves should travel at the speed of light.
LSU Department of Physics & Astronomy professor and collaborator on the CALET experiment on the International Space Station, Michael Cherry, said in the press release the observation has been anticipated by astronomers for some time.
“Gamma-rays are the high-energy electromagnetic counterparts to the LIGO discoveries. Collaborators around the world, including LSU researchers using a telescope on the International Space Station, have been eagerly looking for these events,” Cherry said in the press release. “Now, counterpart observations of this neutron star merger event with several telescopes from the radio to the gamma-ray regime are giving us valuable information about the nature of these exotic astrophysical sources.”
Scientists refer to the events following the collision as a “kilonova.” The light created as a result of the collision spreads throughout space, and becomes much of the gold and silver found in the universe.
This discovery was announced just 13 days after LSU Adjunct Professor and MIT Professor Emeritus Rainer Weiss was among three LIGO scientists to be awarded the 2017 Nobel Prize in Physics for their initial discovery of gravitational waves in 2015.
