Intensely dynamic explosions in the atmosphere are frequently linked to gamma-ray bursts. We now comprehend that these bursts emerge from either the amalgamation of two neutron stars or the implosion of a gigantic star. In these instances, a newly formed black hole is created, emitting a jet that travels at almost the speed of light. When these jets are aimed towards Earth, we can detect them from immense distances — occasionally billions of light-years away — owing to a relativistic phenomenon known as Doppler boosting. Over the past decade, thousands of such gamma-ray bursts have been identified.

Since its inauguration in 2024, the Einstein Probe — an X-ray space observatory designed by the Chinese Academy of Sciences (CAS) in collaboration with the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics — has been surveying the skies in search of dynamic explosions. In April, the observatory recorded an extraordinary occurrence referred to as EP240408A. An international group of astronomers, including Dheeraj Pasham from MIT, Igor Andreoni from the University of North Carolina at Chapel Hill, Brendan O’Connor from Carnegie Mellon University, and others, have analyzed this explosion utilizing a variety of ground-based and space-based telescopes, including NuSTAR, Swift, Gemini, Keck, DECam, VLA, ATCA, and NICER, which was developed in collaboration with MIT.

An open-access report of their discoveries, published on Jan. 27 in The Astrophysical Journal Letters, reveals that the features of this explosion do not conform to those of standard gamma-ray bursts. Instead, it may signify a rare new category of powerful cosmic explosion — a jetted tidal disruption phenomenon, which transpires when a supermassive black hole disrupts a star.

“NICER’s capability to maneuver to nearly any section of the sky and monitor for extended periods has been crucial in enhancing our understanding of these peculiar cosmic explosions,” states Pasham, a research scientist at the MIT Kavli Institute for Astrophysics and Space Research.

Although a jetted tidal disruption event is conceivable, the researchers note that the absence of radio emissions from this jet is perplexing. O’Connor suggests, “EP240408A satisfies some of the criteria for various phenomena, but it doesn’t meet all the criteria for any specific one. Particularly, the brief duration and high luminosity are difficult to account for with other hypotheses. The alternative is that we might be observing something completely unprecedented!”

Pasham indicates that the Einstein Probe is only beginning to uncover what may be achievable. “I’m thrilled to pursue the next peculiar explosion from the Einstein Probe,” he remarks, reflecting the enthusiasm of astronomers globally who anticipate the chance to uncover more extraordinary explosions from the distant corners of the universe.