Einstein Probe Observes the X-ray Sky with Wide Eyes

The recent images captured by the Einstein Probe mission provide an exciting look into the capabilities of this innovative spacecraft. Presented at the 7th workshop of the Einstein Probe consortium in Beijing, these images showcase the spacecraft’s novel optics, which mimic a lobster’s eyes, and demonstrate its readiness to monitor the X-ray sky.

Launched on January 9, 2024, the Einstein Probe is a collaborative mission led by the Chinese Academy of Sciences (CAS). In partnership with ESA, the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany, and the National Centre for Space Studies (CNES) in France, the mission aims to explore the Universe using X-ray light. Over the past few months, the mission operations team has been conducting tests to ensure that the spacecraft is functioning properly and calibrating the scientific instruments.

The first-light images captured by Einstein Probe highlight the extraordinary capabilities of its two scientific instruments – the Wide-field X-ray Telescope (WXT) and the Follow-up X-ray Telescope (FXT). The WXT can observe nearly one-eleventh of the celestial sphere in one shot, providing a wide panorama of the X-ray sky. Meanwhile, the FXT offers close-up views and can pinpoint short-lived events detected by the WXT.

“I am delighted to see the first observations from Einstein Probe, which showcase the mission’s ability to study wide expanses of the X-ray sky and quickly discover new celestial sources,” says Prof. Carole Mundell, ESA Director of Science. These early findings provide a glimpse into the high-energy dynamic Universe that will soon be accessible to our science communities.

One of the key features of Einstein Probe is its ability to promptly detect new X-ray sources and monitor their evolution over time. This capability especially important for understanding the most energetic processes in the cosmos, such as neutron star collisions, supernova explosions, and black hole interactions. The spacecraft’s wide-field instrument, the WXT, has already detected a variety of energetic objects and transient X-ray sources during its initial months in space.

The lobster-eye optics of the WXT are based on a breakthrough technology tested in a 2022 flight by the technology demonstrator LEIA (Lobster Eye Imager for Astronomy). These optics enable the spacecraft to monitor the entire night sky in just three orbits, providing a comprehensive view of X-ray emissions. The detections made by the WXT resemble a lit-up plus sign, showcasing the unique capabilities of this instrument.

In addition to its wide-field observations, Einstein Probe’s FXT instrument allows for detailed studies of X-ray-emitting objects and events. The FXT has already captured stunning images of a supernova remnant, an elliptical galaxy, a globular cluster, and a nebula. Notably, the FXT performed a follow-up observation of an X-ray event first spotted by the WXT, indicating its reliability and potential for time-critical observations.

In the coming months, Einstein Probe will continue with calibration activities before commencing routine science observations around mid-June. Throughout its three-year mission, the spacecraft will orbit Earth at a height of 600 km, monitoring the sky for transitory X-ray events. The FXT follow-up telescope will provide a closer look at these events and other intriguing objects. These observations will complement the in-depth studies of individual cosmic sources conducted by other X-ray missions like ESA’s XMM-Newton and JAXA’s XRISM.

The data collected by Einstein Probe will not only advance our understanding of high-energy phenomena in the Universe but also contribute to preparations for future X-ray missions. The mission’s capabilities align with ESA’s NewAthena mission, currently in development, which aims to be the largest X-ray observatory ever built.

It is worth noting that the Einstein Probe mission is an international collaboration led by CAS, with contributions from ESA, MPE, and CNES. ESA’s involvement includes providing key components for the FXT and supporting the testing and calibration of the X-ray detectors and optics of the WXT. ESA’s ground stations will facilitate data download, and CNES will provide a ground receiving network for real-time and fast data transmission. In return for its contributions, ESA will have access to 10% of the scientific data collected by Einstein Probe.

The recent images captured by the Einstein Probe mission are a testament to the remarkable achievements of this collaborative endeavor. With its lobster-eye optics and advanced scientific instruments, this spacecraft is set to revolutionize our understanding of the Universe in X-ray light. As the mission progresses, we can expect more groundbreaking discoveries that will shape our knowledge of high-energy astrophysics.