On July 4, 2025, the Einstein Probe space observatory detected a signal, designated EP250704a, which originated approximately six billion years ago. The event began with a 0.5-second gamma-ray burst, followed by an intense X-ray emission that lasted for about ten minutes.
Researchers utilized the Very Large Telescope (VLT) and the Very Large Array (VLA) to analyze the event. According to astronomer Niccolo Passaleva, this duration of initial X-ray emission during a neutron star merger is unprecedented in previous observations.
The scientific team suggests that the collision of two neutron stars likely formed a magnetar, a dense object with an exceptionally strong magnetic field. This magnetar could have continuously supplied energy to the surrounding material, sustaining the X-ray emission after the primary explosion.
While alternative theories like a supernova were considered, the observational data did not support them. Researchers view the magnetar hypothesis as the most probable explanation for the event, though further studies are required to confirm this theory and clarify the origins of other mysterious X-ray bursts.
