In a first, astronomers observe fiery explosion caused by neutron star merger

For the first time, scientists have recorded millimeter-wavelength light from a fiery explosion caused by the merger of a neutron star - the dense, collapsed core of a massive star that exploded as a supernova - with another star, thanks to the unparalleled sensitivity of the Atacama Large Millimeter/submillimeter Array (ALMA), the world's largest ground-based facility for observations in the millimeter/submillimeter regime.

The researchers also confirmed this flash of light to be one of the most energetic short-duration gamma-ray bursts (GRBs) ever observed. GRBs are the most powerful explosions the Universe has seen since the Big Bang. They are capable of emitting more energy in a matter of seconds than our Sun will emit during its entire lifetime.

Scientists believe that short-duration GRBs are responsible for the creation of the heaviest elements in the Universe, such as platinum and gold. They usually last only a few tenths of a second.

"These mergers occur because of gravitational wave radiation that removes energy from the orbit of the binary stars, causing the stars to spiral in toward each other. The resulting explosion is accompanied by jets moving at close to the speed of light. When one of these jets is pointed at Earth, we observe a short pulse of gamma-ray radiation or a short-duration GRB," Tanmoy Laskar, who will soon commence work as an Assistant Professor of Physics and Astronomy at the University of Utah, said in a statement.

According to the researchers, the light from this short-duration gamma-ray burst, GRB 211106A, was so faint that while early X-ray observations with NASA's Neil Gehrels Swift Observatory saw the explosion, the host galaxy was undetectable at that wavelength, and scientists weren’t able to determine exactly where the explosion was coming from.

"This short gamma-ray burst was the first time we tried to observe such an event with ALMA. Afterglows for short bursts are very difficult to come by, so it was spectacular to catch this event shining so bright," said Wen-fai Fong, an Assistant Professor of Physics and Astronomy at Northwestern University.