NASA Chandra Discovers Neutron Star Collision in Unique Galactic Setting

Astronomers using NASA's Chandra X-ray Observatory and other telescopes have identified a likely collision between two neutron stars in a tiny galaxy buried within a long stream of gas. This is the first time such a collision has been observed in this setting. The galaxy lies about 4.7 billion light-years away and sits inside a gas stream roughly 600,000 light-years long. The stream probably formed hundreds of millions of years ago during a collision between groups of galaxies that stripped material into intergalactic space. The associated gamma-ray burst, called GRB 230906A, was first detected in September 2023 by NASA's Fermi Gamma-ray Space Telescope. Follow-up observations with the Neil Gehrels Swift Observatory, Chandra, and the Hubble Space Telescope narrowed the location to the faint galaxy. Chandra data supplied a precise position that enabled Hubble to detect the tiny galaxy at that spot. The event may help explain how heavy elements such as gold and platinum appear in stars far from galaxy centers and why some gamma-ray bursts lack clear ties to known galaxies. A paper on the findings has been accepted in The Astrophysical Journal Letters.