In May this year, a collision between neutron stars emitted so much light that the largest telescopes on the planet turned to see the radiation emissions typical of black hole formation – and what they witnessed was the birth of a magnetar.
Published in the Astrophysical Journal, the study to understand the intense glare captured involved scientists from both NASA’s Hubble and Neil Gehrels Swift Observatory space telescopes, both from NASA and ground-based telescopes. Occurring 5.47 billion light years from Earth, the explosion emitted bursts that ran across the electromagnetic spectrum – from radio waves to gamma rays. The infrared emission detected by Hubble was also disconcerting: ten times brighter than expected at similar events.
. Harvard & Smithsonian / Center for Astrophysics / Disclosure
“Hubble’s observations were programmed to research the infrared emission resulting from the creation of heavy elements, such as gold, platinum and uranium, during a collision of neutron stars, which gives rise to a short burst of gamma rays. Surprisingly, we found an emission far brighter than we expected, “said Harvard & Smithsonian Center for Astrophysics astronomer and principal investigator for the Hubble program, Edo Berger.
Scattered around the planet, the researchers began to discuss what could have caused the unusual level of brightness captured by Hubble. According to Berger, it was a question of answering a question: “What is left behind in such a collision: a more massive neutron star or a black hole?”
Hubble had the answer
It has long been suspected that small explosions of gamma rays (which normally last less than two seconds) are generated by the collision between neutron stars. These stellar corpses are what remains when a supermassive star collapses on itself; their nucleus compresses in such a way that they can have the mass of the Sun and the size of a small town.
The expected result is the emission of light from the radioactive decay of the heavy elements that are formed in the fusion of two neutron stars (this glow is a thousand times more intense than that emitted by a supernova) and the appearance of a black hole.
The data collected from the observations frustrated astronomers. “The infrared emission captured by Hubble was brighter than expected. In that huge puzzle that was a gamma-ray explosion, a piece was not fitting correctly,” said Northwestern astronomer and lead author of the study, Wen -Fai Fong.