An animated simulation of China's Einstein Probe satellite operating in space. /CFP
China's Einstein Probe (EP) satellite has detected a mysterious, transient celestial object that flickers like fireworks, the Chinese Academy of Sciences (CAS) announced in initial results published on Thursday.
The previously unseen transient object shows spectral and temporal features that don't match any known types, potentially providing exciting new insights into the universe and extreme physical processes. The fleeting cosmic "fireworks" could carry key information about the formation and evolution of celestial bodies, making them crucial for studying extreme phenomena of the cosmos, according to CAS affiliated media outlet ScienceNet.
Known as EP240408a, the transient event was detected on April 8 by the EP satellite. It recorded a violent X-ray flare that increased in brightness by 300 times and lasted for only 12 seconds before fading away. The X-ray emissions from this source disappeared about 10 days later.
"It is difficult for other X-ray and multi-wavelength telescopes to detect," said Yuan Weimin, principal investigator of the EP mission and a researcher at the National Astronomical Observatories of CAS.
"This finding suggests that our previous understanding of transient celestial phenomena may be just the tip of the iceberg," Yuan added.
The recent discovery has been published in the latest issue of the Chinese academic journal SCIENCE CHINA: Physics, Mechanics & Astronomy.
The first X-ray all-sky map captured by EP (under Galactic coordinates). /ScienceNet
China's Einstein Probe
Launched in January this year, the EP satellite adopts new X-ray detection technology with the two payloads it carries: a Wide-field X-ray Telescope (WXT) and a Follow-up X-ray Telescope. Inspired by the structure of the lobster eye, the WXT was developed to achieve wide-field observation and X-ray-focused imaging simultaneously.
During its commissioning and initial operation phase, the EP satellite has detected 60 confirmed transient events and many more candidates, including stars, white dwarfs, neutron stars, black holes, supernovae and gamma-ray bursts, according to Yuan. It also sent back X-ray images of the moon in September.
In addition, it has detected a gamma-ray burst, coded EP240315a, some 25.6 billion light-years away. This discovery demonstrates the satellite's capacity for detecting gamma-ray bursts from the distant early universe, providing a new perspective for further understanding the physical process of stellar collapse leading to the formation of a black hole and relativistic jets, according to Yuan.
"EP has proven the importance of wide-field monitoring of the X-ray sky. The survey and follow-up capabilities have allowed for the discovery of numerous new X-ray transients and the regular monitoring of known sources. EP's discoveries show that it is already having a major effect on science," said Paul O'Brien, head of astrophysics at the University of Leicester's School of Physics and Astronomy.
(With input from Xinhua)