EP251023a: A fast X-ray transient featuring a magnetar-powered optical internal plateau followed by a steep decay

Shuai-Qing Jiang, Dong Xu, Wei-Hua Lei +33

EP251023a is an extragalactic fast X-ray transient (eFXT) detected solely by EP without a gamma-ray counterpart. The prompt emission consists of a main emission with a duration $T_…