South Coast Astronomers Observe Astronomical Phenomenon That Was Little More Than Theory For Years

Oct 16, 2017

An astronomical phenomenon that has been a theory for years has finally been proven. Astronomers on the South Coast were part of an international group of researchers that observed this incredible cosmic event.

A dome opens up around a one-meter robotic telescope at Las Cumbres Observatory in Goleta. The observatory -- known as LCO -- has built 20 telescopes just like this one that are located all around the world. Several of them were used in the recent discovery of an explosion in space never seen before called a kilonova.

A “chirp” sound was recorded on August 17th by laser detectors at the LIGO observatory in Washington state, indicating microscopic distortion in space caused by gravitational waves. At the same time, NASA’s orbiting Fermi satellite detected a burst of the highest energy light called gamma rays.

“This event is very brief, so you have to be very quick to react. So, we had software that would receive the alert, automatically choose galaxies for us to observe that are in the region where they think the gravitational wave has come from,” said Iair Arcavi, an astronomer and postdoctoral fellow at UC Santa Barbara, who led the effort to use LCO telescopes to observe this kilonova.

He says two neutron stars were merging together about 130 million light-years away. Neutron stars are created from stars that have exploded. They have more mass than the sun but are only ten meters in diameter.

“So, they merge and there’s some amount of material – like 1% of the mass in the system is flung out at speeds that could be 30% the speed of light. That material has a lot of energy that creates radioactive elements when the merger happens. These elements are not stable. So, they then decay and that produces light that we can see for about a week,” Arcavi said.

This flash of light is the kilonova. And LCO was one of six teams around the globe to see it.

“It’s incredible. This is something that came out of people doing calculations on computers and paper. And it turns out the universe really makes that thing,” Arcavi said.

Curtis McCully, an astronomer and postdoctoral fellow at USCB and LCO, says images were taken from the observatory’s robotic telescopes in Chile, South Africa and Australia. He says he was surprised at how something so tremendous and bright – about 200 million times brighter than the sun -- could fade so quickly.

“Everybody get every telescope that we can get a hold of and start looking at this object to try to get as much data before it fades away and we miss our chance. This is one of the really important things about Las Cumbres. Because we have telescopes situated around the whole world, we could follow this in real time,” he said.

That’s how the LCO team was able to view the kilonova for virtually continuous coverage.

McCully says this could help scientists learn more about one of the most precious elements that you may find in your jewelry box.

“One of the reasons we call it an explosion is that it's such hot material that it does fusion. And it produces heavy elements. So, say all the gold on earth may have been produced by kilonovae,” he said.

This is the first time that astronomers have used light and gravitational waves to detect an astronomical event. The discovery of the kilonova is considered a game-changer for astrophysics. This is just the beginning, says Arcavi.

“We can’t tell you right now what kind of implications something like this will have. But, from experience, every time we’ve opened a new window in the universe, we’ve discovered something new that we have not imagined before. And I don’t think this is going to be any different,” he said.