Mar 05, 2024
X-Ray Imaging and Spectroscopy Mission (XRISM) satellite enters nominal phase, with release of early scientific observation data
Keyword:RESEARCH
OBJECTIVE.
Rikkyo University researchers comprising Senior Specially Appointed Professor Shunji Kitamoto, Associate Professor Shinya Yamada, and Assistant Professor Makoto Sawada of the Department of Physics, College of Science, and graduate students in physics have joined an international team to jointly develop a soft X-ray spectrometer, called Resolve, for the use onboard the XRISM satellite. The team was formed by Japan (Japan Aerospace Exploration Agency, or JAXA, and others), the United States (NASA, LLNL, and others), and the Netherlands (SRON).
The XRISM satellite and its onboard mission equipment have completed their commissioning phase, and have entered the nominal phase. In the phase, the XRISM first conducts astronomical observations to understand the capabilities of the satellite’s onboard instruments, along with calibration and initial performance verification to improve observation accuracy. The XRISM will then start astronomical observations based on proposals from researchers around the world.
The X-Ray Imaging and Spectroscopy Mission (XRISM) is an international joint mission for precise observations of high-temperature plasma objects in space. XRISM has achieved excellent instrumental performance in orbit, including spectroscopic performance that exceeds the initial target. It is expected to lead to various discoveries in the future. Some of the early science observation data are presented below.
The center of the Perseus cluster of galaxies obtained with the soft X-ray spectrometer (Resolve)
Figure 1 shows a spectrum of the central region of the Perseus cluster of galaxies, obtained with XRISM’s onboard soft X-ray spectrometer (Resolve). The Perseus cluster of galaxies is located about 240 million light years from Earth. It is the most luminous giant cluster of galaxies in X-rays (Note 1). The constellation Perseus is located immediately next to Cassiopeia, which is known for its “W” shape.
The precise X-ray spectra from Resolve enables to precisely measure the temperature and velocity of the plasma, thereby revealing the distribution and motion of dark matter, which plays an important role in the dynamical evolution of the universe. This data is expected to reveal how clusters of galaxies have formed and how they will evolve.
The precise X-ray spectra from Resolve enables to precisely measure the temperature and velocity of the plasma, thereby revealing the distribution and motion of dark matter, which plays an important role in the dynamical evolution of the universe. This data is expected to reveal how clusters of galaxies have formed and how they will evolve.
Figure 1.
Figure 1: X-ray spectrum of the Perseus cluster of galaxies obtained with XRISM’s onboard soft X-ray spectrometer (Resolve). The background image is a composite image of X-ray, visible light, and radio wave around the observation area. The bright center is NGC 1275, the galaxy located at the center of the Perseus cluster. The small square in the upper right corner shows a magnified view of a spectrum from 6 keV to 7 keV.
(Credit: JAXA/NASA/CXC*/IoA**/A.Fabian et al./NRAO/VLA/G. Taylor/ESA/Hubble Heritage (STScI/AURA) /Univ. of Cambridge) * Chandra X-ray Center ** the Institute of Astronomy in Cambridge, UK
(Credit: JAXA/NASA/CXC*/IoA**/A.Fabian et al./NRAO/VLA/G. Taylor/ESA/Hubble Heritage (STScI/AURA) /Univ. of Cambridge) * Chandra X-ray Center ** the Institute of Astronomy in Cambridge, UK
Image of the supernova remnant SN 1006 obtained with the soft X-ray imager (Xtend)
Figure 2.
Figure 2: X-ray and visible light composite image of the supernova remnant SN 1006. The X-ray image was obtained with the soft X-ray imager (Xtend) onboard XRISM.
(Credit: X-ray: JAXA/Optical: DSS*** ) ***The Digitized Sky Survey
(Credit: X-ray: JAXA/Optical: DSS*** ) ***The Digitized Sky Survey
Figure 2 shows an X-ray image of supernova remnant SN 1006 obtained with XRISM’s onboard soft X-ray imager (Xtend). This object is the remnant of a supernova (Note 2) that exploded around the time of famous historical figures Murasaki Shikibu and Fujiwara no Michinaga. It is located in the direction of the constellation Lupus, about 7,000 light years from Earth. SN 1006 has expanded into a large spherical object 65 light years in diameter over a little longer than 1,000 years since its explosion, and is still expanding at 5,000 kilometers per second.
The supernova remnant SN 1006 has an apparent size about the same as the full moon and a visual apparent diameter of about 30 arc minutes. Thanks to Xtend’s wide field of view, the object fit entirely in the image taken. This data will allow a detailed study of the abundance of elements created by the fusion reaction during the explosion, as well as how the remnant is expanding.
The supernova remnant SN 1006 has an apparent size about the same as the full moon and a visual apparent diameter of about 30 arc minutes. Thanks to Xtend’s wide field of view, the object fit entirely in the image taken. This data will allow a detailed study of the abundance of elements created by the fusion reaction during the explosion, as well as how the remnant is expanding.
Future observation results
Some of the scientific observation data obtained after first light observations are now accessible on the JAXA website for researchers (Note 3). This resource aims to support researchers around the world who are planning observation proposals to make appropriate proposals by accurately understanding the performance of XRISM. Future updates on observation results will be provided on the JAXA website and other media.
Supplemental information
Note 1: A galaxy cluster is composed of numerous galaxies with a diameter of 10 million light years and is called the most expansive structure in the universe. Galaxies are drawn together by the gravitational pull of a mysterious substance known as “dark matter.” This gravitational pull attracts galaxies and draws in hydrogen gas generated in the universe's early stage. This drawn-in hydrogen gas transformed into ultra-hot plasma, reaching tens of millions of degrees Kelvin and emitting vibrant X-ray radiation.
Note 2: A supernova is a very luminous celestial event resulting from a violent explosion originating from a massive star or white dwarf. SN 1006 is thought to have resulted from an explosion of a white dwarf. A white dwarf is a dense remnant left behind after a Sun-like star ends its life. When a white dwarf forms a binary star system with another star, matter from the white dwarf’s companion star accretes to the white dwarf, triggering runaway nuclear fusion within the white dwarf. The energy from the fusion causes the entire white dwarf to explode.
Note 3: JAXA website for researchers
Note 2: A supernova is a very luminous celestial event resulting from a violent explosion originating from a massive star or white dwarf. SN 1006 is thought to have resulted from an explosion of a white dwarf. A white dwarf is a dense remnant left behind after a Sun-like star ends its life. When a white dwarf forms a binary star system with another star, matter from the white dwarf’s companion star accretes to the white dwarf, triggering runaway nuclear fusion within the white dwarf. The energy from the fusion causes the entire white dwarf to explode.
Note 3: JAXA website for researchers