A powerful cosmic outburst has been observed by the Einstein Probe, leaving astronomers puzzled as it defies typical gamma-ray bursts. Could this be a new class of explosion – a jetted tidal disruption event?
The study of highly energetic explosions in the sky has led to a deeper understanding of gamma-ray bursts, which are commonly attributed to either the merger of two neutron stars or the collapse of a massive star. These events result in the formation of a newborn black hole, emitting a jet that travels at nearly the speed of light and can be observed from vast distances due to Doppler boosting.
The Einstein Probe Uncovers an Enigmatic Event
Since its launch in 2024, the ‘Einstein Probe, an X-ray space telescope developed by the Chinese Academy of Sciences (CAS) in partnership with the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics’ has been scanning the skies for energetic explosions. In April, the telescope observed an unusual event designated as EP240408A. An international team of astronomers, including Dheeraj Pasham from MIT, Igor Andreoni from University of North Carolina at Chapel Hill, and Brendan O’Connor from Carnegie Mellon University, among others, have investigated this explosion using a range of ground-based and space-based telescopes.
The Einstein Probe is a space mission designed to study high-energy particles and gamma-ray bursts from distant cosmic sources.
Launched in 2023, this probe aims to explore the universe's most energetic phenomena.
Equipped with advanced detectors, it will analyze particle interactions and radiation patterns to gain insights into dark matter, dark energy, and the fundamental laws of physics.
The Einstein Probe is a collaborative project between European Space Agency (ESA) and NASA, marking a significant step in humanity's quest for understanding the cosmos.
Characteristics Defy Typical Gamma-Ray Bursts
The characteristics of EP240408A do not match those of typical gamma-ray bursts. Instead, it may represent a rare new class of powerful cosmic explosion – a jetted tidal disruption event. This occurs when a supermassive black hole tears apart a star. The researchers used the NICER telescope’s ability to steer and monitor for weeks to understand these unusual cosmic explosions.
Jetted tidal disruption events (TDEs) are a rare and extreme phenomenon occurring when a star passes close to a supermassive black hole.
As the star is torn apart, a jet of energy is released, potentially causing a bright flare.
Studies suggest that TDEs can provide valuable insights into the properties of black holes and their environments.
Astronomers have detected several TDEs in recent years, with observations indicating that these events may be more common than previously thought.
Further research is needed to fully understand the mechanisms behind jetted TDEs.
A Puzzling Lack of Radio Emissions
While a jetted tidal disruption event is plausible, the researchers note that the lack of radio emissions from this jet is puzzling. O’Connor surmises, ‘EP240408a ticks some of the boxes for several different kinds of phenomena, but it doesn’t tick all the boxes for anything.’ The short duration and high luminosity are hard to explain in other scenarios, leading the researchers to consider that they may be observing something entirely new.
Unveiling the Secrets of EP240408A
According to Pasham, the Einstein Probe is just beginning to scratch the surface of what seems possible. ‘I’m excited to chase the next weird explosion from the Einstein Probe,’ he says, echoing astronomers worldwide who look forward to discovering more unusual explosions from the farthest reaches of the cosmos. The investigation of EP240408A has opened up new avenues for research and has sparked a sense of excitement among astronomers about what other secrets lie hidden in the universe.
