Note: Single-source report; awaiting corroboration.
NASA’s Fermi Gamma-ray Space Telescope identified gamma-ray signals from the rare superluminous supernova SN 2017egm, located in galaxy NGC 3191 about 440 million light-years from Earth. This supernova produced roughly ten times the visible light of typical supernovae, making it one of the closest such events ever observed.
An international research team analyzed data from Fermi's Large Area Telescope, focusing on the six nearest superluminous supernovae detected in the first 16 years of the mission. SN 2017egm was the only one to show clear evidence of gamma rays, marking the first definitive detection from this type of supernova.
Core-collapse supernovae like SN 2017egm occur when massive stars exhaust their fuel, collapse, and explode, potentially forming neutron stars or black holes. Researchers propose that the intense light and gamma-ray emission from SN 2017egm are powered by a magnetar—an extremely magnetized neutron star born from the collapse.
The discovery provides a new method to study superluminous supernovae using their gamma-ray signatures, advancing understanding of the universe's most energetic stellar explosions.
The findings were detailed in a paper published in the journal Astronomy & Astrophysics by a collaboration including scientists from NASA, the French National Centre for Scientific Research, University of Paris-Saclay, and others.