Invisible to our eyes, X-rays emitted by the hot gas filling much of the Universe can illuminate many cosmic mysteries. The ‘first light’ observations of this gas by JAXA’s X-ray Imaging and Spectroscopy Mission (XRISM) are now ready. They demonstrate that the mission will play a big role in unveiling the evolution of the Universe and the structure of spacetime.
Galaxy cluster Abell 2319
XRISM’s first test images show a cluster of galaxies and a supernova remnant – the husk left behind when a massive star explodes. What’s more, XRISM has measured the energy of incoming X-rays from the supernova remnant to reveal the chemical elements contained within it.
The observations showcase the extraordinary capability of XRISM’s two science instruments. They were made during the mission’s ‘commissioning phase’ – when engineers carry out all the tests and checks needed to make sure the spacecraft is working as well as possible.
X-ray images of the cosmos are special. They look very different to the images we are used to seeing in visible and infrared light, such as those from the James Webb and Hubble Space Telescopes. They also convey unique information about the Universe’s most dramatic phenomena, as X-rays are a very high-energy type of light emitted in the hottest and most violent events.
XRISM is a collaboration between the Japan Aerospace Exploration Agency (JAXA) and NASA, with significant participation from ESA. In return for providing hardware and scientific advice, ESA is allocated 8% of XRISM’s available observing time.
“It’s so exciting to see XRISM already carrying out such marvellous scientific observations, even though it is not yet fully calibrated,” says ESA Director of Science Carole Mundell. “It shows the potential this mission offers to our science communities for groundbreaking discoveries in the study of the most energetic phenomena in the Universe.”
“I congratulate the engineering teams at JAXA, ESA and NASA for reaching this important milestone.”
Galaxy cluster Abell 2319
This pioneering image is a wide view of a nearby cluster of galaxies called Abell 2319. In purple we see X-ray light from million-degree gas that permeates between the galaxies in the cluster. Observing this gas helps astronomers measure the total mass of the galaxy cluster, revealing information about the birth and evolution of the Universe.
XRISM’s observations of galaxy clusters will also provide insight into how the Universe produced and distributed the chemical elements that we find on Earth today. The hot gas found within clusters is a remnant of the birth and death of stars over billions of years. By studying the X-rays emitted by the gas, XRISM will discover which ‘metals’ (elements heavier than hydrogen and helium) it contains and map how the Universe became enriched with them.
This image of Abell 2319 was taken with XRISM’s Xtend instrument, which uses a CCD camera to image extended X-ray emitting objects and their surroundings. Xtend’s unique ability to capture the entire cluster in a single shot promises a significant step forward in our understanding of the large-scale structure of the Universe.
Source: European Space Agency