XRISM Mission Reveals First Images of the Cosmos Using X-ray Space Telescope

The XRISM (X-ray Imaging and Spectroscopy Mission) observatory has released a first glimpse into the unprecedented data it will collect when scientific operations begin later this year.

New Era in X-Ray Astronomy

On September 6, 2023, the Japan Aerospace Exploration Agency (JAXA) launched XRISM in collaboration with NASA and ESA. This new astronomical satellite, designed to detect X-rays with energies up to 12,000 electron volts, aims to study the hottest regions, largest structures, and objects with the strongest gravity in the universe.

According to Richard Kelley, the US principal investigator for XRISM, the observatory will give the international scientific community a new glimpse of the hidden X-ray cosmos. It will allow the observation of these sources' X-ray images and provide more insights into their motions, compositions, and physical states.

XRISM uses two instruments, Resolve and Xtend, each at the focus of an X-ray Mirror Assembly designed and built at Goddard Space Flight Center in Greenbelt, Maryland. Resolve is a microcalorimeter spectrometer created by JAXA and NASA. It works at just a fraction of a degree above absolute zero inside a liquid helium container.

When an X-ray hits the 6-by-6-pixel detector of Resolve, the device gets warm by an amount related to its energy. Then, it provides previously unavailable information about the source by measuring each X-ray energy.

Meanwhile, Xtend is an X-ray imager developed by JAXA. It provides XRISM with a large field of view by allowing the satellite to observe an area about 60% larger than the average apparent size of the full moon.

A New View of the Cosmos

Astronomers used Resolve to explore N123D, a supernova remnant considered one of the brightest X-ray sources in the Large Magellanic Cloud. The wreckage is assumed to be about 3,000 years old and was formed when a star 15 times the mass of the Sun ran out of fuel and exploded.

The resolve spectrum also revealed peaks associated with sulfur, argon, silicon, calcium, and iron. These elements were produced in the original star and got scattered when it exploded as a supernova. This discovery is considered the most detailed X-ray spectrum of the object ever obtained.

According to NASA's XRISM project scientist Brian Williams, Resolve lets them determine the abundances of different elements and their densities, temperatures, and directions of motion with very high precision. From there, they can piece together information regarding the origin and explosion of a star.

On the other hand, Xtend helped the experts capture an X-ray image of Abell 2319, a rich galaxy cluster about 770 million light-years away in the northern constellation Cygnus. It is considered the fifth brightest X-ray cluster in the sky and is undergoing a major merger event. The cluster measures 3 million light-years across, highlighting Xtend's wide field of view.

Resolve performs exceptionally well despite concerns about the aperture door that covers its detector. The door was designed to protect the detector before launch but has not opened as planned after several attempts. Since the door blocks lower-energy X-rays, it cuts the mission off at 1,700 electron volts compared to the planned 300.