Astronomers detect record X-ray flash potentially revealing magnetar birth

Astronomers have captured a record-breaking X-ray transient, designated EP250704a/GRB 250704B, which may provide evidence of a magnetar being born from a neutron star collision. The event was initially flagged by the Einstein Probe satellite on July 4, 2025. While typical short gamma-ray bursts often vanish in less than two seconds, this event featured a half-second gamma-ray burst followed by a continuous X-ray flash lasting nearly ten minutes.

Following the initial detection, researchers utilized rapid-response protocols to conduct follow-up observations using the European Southern Observatory’s Very Large Telescope (VLT) and the Very Large Array. Spectroscopic analysis via the VLT’s X-Shooter instrument allowed the team to determine a redshift of z=0.6610, placing the source over six billion light-years away.

The findings, supported by research from Professor Eleonora Troja’s group, suggest that some neutron star mergers produce long-lasting X-ray flashes rather than just brief gamma-ray bursts. This discovery helps explain certain mysterious cosmic flashes and provides a new way to identify the formation of rapidly spinning magnetars resulting from stellar remnants merging.