Japan's XRISM satellite showcases 1st look at X-ray cosmos

WASHINGTON: Japan Aerospace Exploration Agency's (JAXA) X-ray Imaging and Spectroscopy Mission (XRISM) observatory has released a first look at the unprecedented data it will collect when science operations begin later this year.

The XRISM (pronounced “crism”) satellite was launched on September 6, 2023, alongwith SLIM (Smart Lander for Investigating Moon), which entered the lunar orbit on Christmas day and aims to make the nation's first-ever moon landing on January 20.

The satellite’s science team released a snapshot of a cluster of hundreds of galaxies and a spectrum of stellar wreckage in a neighbouring galaxy, which gives scientists a detailed look at its chemical makeup.

“XRISM will provide the international science community with a new glimpse of the hidden X-ray sky,” said Richard Kelley, the US principal investigator for XRISM at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“We’ll not only see X-ray images of these sources, but also study their compositions, motions, and physical states,” Kelley added.

XRISM is in collaboration with NASA, along with contributions from ESA (European Space Agency).

It’s designed to detect X-rays with energies up to 12,000 electron volts and will study the universe’s hottest regions, largest structures, and objects with the strongest gravity. For comparison, the energy of visible light is 2 to 3 electron volts.

The mission has two instruments, Resolve and Xtend, each at the focus of an X-ray Mirror Assembly designed and built at Goddard.

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

When an X-ray hits Resolve’s 6-by-6-pixel detector, it warms the device by an amount related to its energy. By measuring each individual X-ray’s energy, the instrument provides information previously unavailable 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 around 160,000 light-years away in the southern constellation Dorado.

The expanding wreckage is estimated to be about 3,000 years old and was created when a star roughly 15 times the Sun’s mass ran out of fuel, collapsed, and exploded.

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

XRISM’s second instrument, Xtend, is an X-ray imager developed by JAXA. It gives XRISM a large field of view, allowing it to observe an area about 60 per cent larger than the average apparent size of the full moon.

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

The cluster is three million light-years across and highlights Xtend’s wide field of view.