NASA’s Fermi telescope reveals the power source behind monster supernovae

NASA's Fermi Gamma-ray Space Telescope may have finally uncovered what powers some of the brightest stellar explosions ever observed. After studying years of data, an international research team found strong evidence that a rare superluminous supernova was energized by an extremely magnetic neutron star formed during the star's collapse. The Fermi mission is part of NASA's network of observatories designed to track changing events across the universe and help scientists better understand how cos

"For nearly 20 years, astronomers have searched Fermi data for gamma-ray signals from thousands of supernovae, and while a few intriguing hints have been reported, none were definitive until now," study lead Fabio Acero at the French National Centre for Scientific Research (CNRS) and the University of Paris-Saclay. The findings were published in the journal Astronomy & Astrophysics . Core-collapse supernovae occur when a massive star exhausts the fuel needed to support its core. Without that energy source, the core collapses under gravity and triggers a violent explosion. Depending on conditions, the collapse can leave behind either a neutron star or a black hole. The rest of the star is blasted outward into space as an expanding cloud of extremely hot gas. Over the past two decades, astronomers have identified nearly 400 unusually powerful examples known as superluminous supernovae. These rare explosions can shine at least 10 times brighter in visible light than ordinary supernovae. In 2024, researchers led by Li Shang at Anhui University in Hefei, China, suggested that Fermi's Large Area Telescope may have detected gamma rays from one of these events years after the explosion occurred. The object, called SN 2017egm, erupted in the galaxy NGC 3191, about 440 million light-years away in the constellation Ursa Major. Even from that enormous distance, it remains one of the closest superluminous supernovae ever observed from Earth. "We searched for gamma rays from the six nearest superluminous supernovae seen during the first 16 years of Fermi's mission," said Guillem Martí-Devesa, a researcher previously at the University of Trieste in Italy and now a fellow at the Institute of Space Sciences in Barcelona, Spain.

Key points

• "For nearly 20 years, astronomers have searched Fermi data for gamma-ray signals from thousands of supernovae, and while a few intriguing hints have been reported, none were definitive until now,"…
• The findings were published in the journal Astronomy & Astrophysics .
• Core-collapse supernovae occur when a massive star exhausts the fuel needed to support its core.
• Without that energy source, the core collapses under gravity and triggers a violent explosion.
• Depending on conditions, the collapse can leave behind either a neutron star or a black hole.