The XRISM mission, led by the Japan Aerospace Exploration Agency (JAXA) and supported by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA), provides new insights into the universe through X-ray imaging of galaxy clusters and supernova remnants, marking a major advance in cosmic exploration.

X-rays emitted by most of the hot gas in the universe, invisible to our eyes, can reveal many cosmic mysteries. The "first light" observations of this gas by Japan Aerospace Exploration Agency's X-ray Imaging and Spectroscopy Mission (XRISM) are now complete. They show that the mission will play an important role in revealing the evolution of the universe and the structure of space and time.

XRISM's first test images show a galaxy cluster and a supernova remnant - the outer shell left behind after a massive star exploded. In addition, XRISM measures the energy of X-rays emitted from supernova remnants to reveal the chemical elements contained within them. These observations demonstrate the extraordinary capabilities of XRISM's two scientific instruments. They were conducted during the mission's "commissioning phase" - a phase where engineers conduct all necessary tests and inspections to ensure the spacecraft is working as well as possible. X-ray images of the universe are special. They look very different from the visible and infrared images we're used to seeing, such as those taken by the James Webb Space Telescope and the Hubble Space Telescope. Because X-rays are a type of very high-energy light emitted during the hottest, most violent events, they can also convey unique information about the universe's most violent phenomena.

XRISM is a collaboration between the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA), with significant participation from ESA. In return for providing hardware and scientific advice, ESA receives 8% of XRISM's available observing time. Carole Mundell, Director of ESA's Science Department, said: "It is exciting that XRISM has already produced such wonderful scientific observations even though it is not yet fully calibrated. This shows that this mission offers our scientific community the potential for groundbreaking discoveries in studying the most energetic phenomena in the universe. I congratulate the engineering teams at JAXA, ESA and NASA for reaching this important milestone."

XRISM Galaxy Group Abell 2319 XRISM's Xtend instrument captured the galaxy cluster Abell 2319 in X-rays, shown here in purple. The background is an image of the ground showing the area in visible light. Image source: JAXA/NASA/XRISMXtend; Background: DSS

This groundbreaking image is a wide-angle view of a nearby galaxy cluster called Abell 2319. In purple, we see X-ray light from million-degree gas that permeates between galaxies in the cluster. Observing this gas helps astronomers measure the total mass of galaxy clusters and reveal information about the birth and evolution of the universe.

XRISM observations of galaxy clusters will also provide insights into how the universe produced and distributed the chemical elements we find on Earth today. The hot gas in galaxy clusters is the remnant of billions of years of star birth and death. By studying the X-rays emitted by the gas, XRISM will discover which "metals" (elements heavier than hydrogen and helium) the gas contains and map how the universe is rich in these elements.

This image of Abell 2319 was taken with XRISM's Xtend instrument, which uses a CCD camera to take extended images of X-ray emitting objects and their surroundings. Xtend's unique ability to capture entire star clusters at once brings our understanding of the large-scale structure of the universe a giant step forward. Learn more.

XRISM's Resolution instrument captured data from supernova remnant N132D in the Large Magellanic Cloud, producing the most detailed X-ray spectrum ever produced for the object. The spectrum shows peaks associated with silicon, sulfur, argon, calcium and iron. The inset on the right is an N132D image taken by XRISM's Xtend instrument. Source: JAXA/NASA/XRISMResolve and Xtend

This colorful image shows the remnants of a massive star that exploded in the nearby Large Magellanic Cloud. Different colors represent different energies of X-ray light, with red having the lowest energy and blue having the highest energy.

XRISM, using its Resolve instrument, was able to supplement Xtend's image of the supernova remnant (top right) to obtain an ultra-clear image of the chemical elements present in N132D. In this way, scientists can calculate the exact location of each element in the supernova remnant.

XRISM can identify each element by measuring the specific energy of the X-ray light it emits. The image above shows separate peaks that were previously indistinguishable; this provides the basis for insights into the formation and distribution of elements in the universe that form the basis of stars, planets and life itself.

Resolve's unique design also allows us to explore the temperature, density and motion of the hot, X-ray-emitting gas in this supernova remnant in more detail than ever before. This will reveal exactly how the remnant interacts with its surroundings, as well as the nature of the explosion that created it in the first place.

The X-ray Imaging and Spectroscopy Mission (XRISM) of the Japan Aerospace Exploration Agency (JAXA) lifted off on an H-IIA rocket from Japan's Tanegashima Space Center at 08:42 Japan time/00:42 Beijing time/01:42 U.S. central time on September 7, 2023. Its successful launch marks the beginning of an ambitious mission to explore the growth of galaxy clusters, the chemical makeup of the universe, and the extremes of space and time. Image source: JAXA

What has JAXA been up to since its launch?

XRISM launched on September 6. Since then, JAXA engineers and scientists have been hard at work getting the telescope ready for scientific research. This includes turning on and testing XRISM's two instruments: Xtend and Resolve.

The spacecraft is currently in good condition. Examinations of onboard systems, such as those that control power, spacecraft orientation and communications with Earth, confirmed that they were working as planned. Hardware provided by ESA was tested early in the commissioning phase and all worked as expected.

The Xtend instrument works brilliantly. The "Resolve" instrument is also performing well. Its energy resolution - a key science performance metric - exceeds even the requirements. However, engineers have not yet been able to open the filter covering the detector, which is designed to protect the detector before and during launch. Efforts are currently underway to resolve the issue, but the XRISM team has decided that planned science observations should assume that the filter will remain in place. The N132D energy spectrum shows that groundbreaking scientific research is still possible.

XRISM will study the universe's X-ray light with an unprecedented combination of light-gathering power and energy resolution (the ability to distinguish X-rays of different energies). The mission will provide a picture of many topics, including the dynamics of galaxy clusters, the chemical makeup of the universe, and the flow of matter around accreting supermassive black holes (active galactic nuclei, or AGNs). Image source: ESA

What's next?

The spacecraft debugging phase will end at the end of January. In February, JAXA will begin calibrating the instrument and demonstrating its capabilities.

As part of a public observing program open to scientists around the world, the observing time allocated to ESA will allow European scientists to seize the extraordinary scientific opportunities presented by Resolution's unprecedented high-resolution spectroscopic capabilities. Scientists have been invited to submit proposals for observations they would like to start in August 2024. The deadline is April 4, 2024.

By combining a large X-ray telescope with state-of-the-art scientific instruments, the Athena telescope will solve key questions in astrophysics, such as: How and why does ordinary matter assemble into celestial bodies? How and why ordinary matter combines into the structures we see today (galaxies, groups and clusters of galaxies) Image source: ESA

Matteo Guainazzi, ESA's XRISM project scientist, said: "These first light images show that XRISM is delivering on its promise to usher in a new era of high-resolution imaging spectroscopy of the hot gases of the universe. Scientists from ESA's member states are warmly encouraged to seize the unique opportunity provided by XRISM and submit proposals for observations using this magnificent telescope."

Observations using XRISM will complement observations made by ESA's XMM-Newton X-ray telescope and will lay a good foundation for the observation plan of ESA's future large-scale mission "New Athena". The latter is designed to significantly exceed the scientific performance of existing spectroscopic and survey X-ray observatories.

Compiled source: ScitechDaily