On November 1, 2024, China's Einstein Probe (EP) satellite detected a mysterious cosmic object exhibiting a firework-like glow. The Chinese Academy of Sciences (CAS) announced the discovery of this transient celestial object, designated EP240408a, which displayed unique spectral characteristics and light patterns.
First observed on April 8, the object emitted an intense X-ray burst, increasing in brightness by 300 times within just 12 seconds before gradually fading away. The source of the X-ray signal disappeared completely after ten days.
Yuan Weimin, lead researcher for the EP mission at the National Astronomical Observatories of CAS, noted, "This discovery indicates that our understanding of transient phenomena in the sky may still be quite limited." The findings have been published in the journal Science China: Physics, Mechanics & Astronomy.
Launched in January 2024, the EP satellite is equipped with advanced technology to detect X-rays using two primary telescopes: the Wide-field X-ray Telescope (WXT) and the Follow-up X-ray Telescope. The WXT, designed to mimic a lobster's eye, allows for wide-area monitoring while focusing on X-rays, capturing rare sky phenomena.
During its initial operational phase, EP confirmed the detection of 60 transient phenomena, including stars, white dwarfs, neutron stars, black holes, supernovae, and gamma-ray bursts. In September, EP even sent back X-ray images of the Moon, demonstrating its exceptional capability to monitor various cosmic objects.
The detection of the transient X-ray event EP240408a brings scientists closer to understanding the formation and evolution of celestial bodies. Each captured cosmic "firework" provides new clues to unraveling the mysteries of the universe.
Additionally, EP recorded a gamma-ray burst designated EP240315a, estimated to be 25.6 billion light-years from Earth. This discovery highlights EP's ability to trace gamma-ray explosions from the early universe, offering new insights into how stellar collapses can form black holes and relativistic jets in the primordial cosmos.
Paul O'Brien, head of astrophysics at the University of Leicester, emphasized the importance of extensive X-ray monitoring in the sky. He stated, "EP's capability to regularly monitor and follow various new objects in the sky has had a significant impact on the scientific community."