The Japanese-led XRISM (X-ray Imaging and Spectroscopy Mission) observatory has provided a first look at the unprecedented data it will collect when scientific operations begin later this year. The satellite’s scientific team released a snapshot of a cluster of hundreds of galaxies and the spectrum of stellar debris in a nearby galaxy, giving scientists a detailed look at the chemical composition of this cluster.

“XRISM will provide the international science community with a new look at the hidden X-ray sky,” said Richard Kelly, XRISM principal investigator at NASA Goddard Space Flight Center in Greenbelt, Maryland. “We will not only see X-ray images of these sources, but also examine their composition, motion and physical state.”

XRISM (pronounced “crisis”) is managed by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, with input from ESA (European Space Agency). It was released on September 6, 2023.

Designed to detect X-rays with energies of up to 12,000 electron volts, it will examine the hottest parts of the universe, the largest structures and objects with the strongest gravity. For comparison, visible light has an energy of 2 to 3 electron volts.

The mission features two devices, Resolve and Xtend, each centered on an X-ray mirror designed and manufactured at Goddard.

Resolve is a microcalorimetric spectrometer developed by NASA and JAXA. It operates just one degree above absolute zero inside a refrigerator-sized container of liquid helium.

When an X-ray beam hits the 6-pixel Resolve 6 detector, it heats the device by an amount proportional to its energy. By measuring the energy of each X-ray, the device provides previously unavailable information about the source.

The mission team used Resolve to study N132D, a supernova remnant and one of the brightest X-ray sources in the Large Magellanic Cloud, a dwarf galaxy about 160,000 light-years away in the southern constellation Dorado. The expanding debris is estimated to be about 3,000 years old and was formed when a star about 15 times the mass of the Sun ran out of fuel and collapsed and exploded.

The Resolve spectrum shows peaks associated with silicon, sulfur, calcium, argon and iron. This is the most detailed X-ray spectrum of the object ever obtained, and showcases the incredible science the mission will do when regular operations begin in late 2024.

“These elements were created in the original star and then exploded when it exploded as a supernova,” said Brian Williams, NASA’s XRISM project scientist at Goddard.

“Resolve will allow us to see the shapes of these lines in a way that has not been possible before, allowing us to determine with unprecedented precision not only the large number of different elements present, but also their temperatures, densities and directions of motion. “We can bring it together.”

XRISM’s second device, Xtend, is an X-ray scanner developed by JAXA. It gives XRISM a wide field of view, allowing it to observe an area approximately 60% larger than the average apparent size of the full Moon.

Xtend took an X-ray image of Abell 2319, a dense galaxy cluster about 770 million light-years away in the northern constellation Cygnus. It is the fifth brightest X-ray cluster in the sky and is currently undergoing a major merger.

The cluster is 3 million light-years across, highlighting Xtend’s wide field of view.

“Even before commissioning is complete, Resolve is already exceeding our expectations,” said Lillian Reichenthal, NASA XRISM project manager at Goddard. “Our goal was to achieve 7 electron volts of spectral resolution with the device, but now that it’s in orbit we’re getting to 5 electron volts. This means we’ll get even more detailed chemical maps with every spectrum that XRISM captures.”

Resolve works extremely well and is already doing some exciting science, despite the issue with the aperture gate covering its detector. The door, designed to protect the detector before launch, did not open as intended after several attempts. The gate blocks low-energy X-rays, shortening the mission by 1,700 electron volts from the planned 300 electron volts. The XRISM team will continue to investigate the anomaly and explore different approaches to open the door. The Xtend tool is not affected.