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[▲Illustration of the Roman Space Telescope (Credit: NASA’s Goddard Space Flight Center)]
The National Aeronautics and Space Administration (NASA) plans to launch the Nancy Grace Roman Space Telescope (herefollowing, the Roman Space Telescope) in May 2027.Revealing the history of the universe through a large-scale galaxy surveyIt is expected that
A research group led by Aaron Yung and others at the NASA Goddard Space Flight Center proposed a method to “rewind” the time of the universe in order to clarify how galaxies and galaxy clusters have evolved. According to the research group, the developed method seems to be completed by the launch of the Roman Space Telescope.
Understanding the formation process of galaxies and galaxy clusters
The large-scale structure of the universe is a “filament-like” structure that is interwoven with regions where galaxies and galaxy clusters are densely packed and regions called voids (supercavities) where galaxies are almost absent. It is believed that this is because the gravity of dark matter, which we cannot directly observe with electromagnetic waves, attracts galaxies and clusters of galaxies.
Regarding the formation of the large-scale structure of the universe, the Λ (lambda) CDM model of the accelerating expansion of the universe, which includes (cold) dark matter and dark energy (dark energy), is recognized as the standard model. According to the standard model of the universe, the gas in the plasma state that filled the early universe had “quantum fluctuations” that attracted dark matter particles. After that, as the expansion of the universe expands the quantum fluctuations, the density of dark matter in the universe will be different. It is said that the large-scale structure of the universe was formed as a result of the formation and coalescence of stars and galaxies due to the gravitational pull of the “dark matter halo”, which is a collection of dark matter particles.
On the other hand, it is extremely difficult to quantitatively treat how the distribution of galaxies and galaxy clusters evolved within the framework of the standard model of the universe. In the formation and evolution of galaxies, many physical processes, such as cooling of interstellar gas, star formation, and supernova explosions, repeat intricately and are not fully understood. I can’t seem to run it.
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The research group performed simulations using well-validated models of galaxy formation. In this simulation,More than 5 millionA hypothetical sky corresponding to the region containing the galaxy of , which is regarding 10 times the apparent size of the full moon, is covered.According to the research group, it will take several years to complete the simulation using the conventional methodtens of millions of galaxiesin this methodless than 1 dayIt is said that it can be simulated with
The ‘Roman’ space telescope ideal for wide-field surveys
The research group positions the observational data obtained by the Roman Telescope to complement our understanding of the relationship between the physical processes that govern star formation and the tendency of star formation.
The Hubble Space Telescope has traditionally played a role in investigating how galaxies formed in the evolutionary history of the universe. But according to Yung, the Hubble Space Telescope and the “James Webb” Space Telescope are optimized for “looking through the eye of a needle” — a narrow field of view.
On the other hand, the Roman Space Telescope is equipped with the same 2.4m diameter primary mirror as the Hubble Space Telescope, but the observation equipment is a 300-megapixel wide-field camera.「WFI（Wide Field Instrument）」will be installed. For this reason, the field of view of the Roman Space Telescope is regarding 100 times wider than that of the Hubble Space Telescope.According to the research group, thanks to such a wide field of view and the rotation speed of the Roman Space Telescope, the Hubble Space Telescope’sregarding 1000 timesIt seems that you can map the area in the universe at the speed of .
Related: NASA’s New Space Telescope Will Be Named ‘Nancy Grace Roman’ (May 22, 2020)
【▲ A simulated image of millions of galaxies scattered in the space-time of a virtual universe. White corresponds to the observation area of the Hubble Space Telescope, and yellow corresponds to the observation area of the Roman Space Telescope. (Credit: NASA’s Goddard Space Flight Center and A. Yung)]
In order to verify the model proposed this time, the research group says that it is essential to actually observe with the Roman Space Telescope. Once the Roman Space Telescope is launched and the data is collected, it will be possible to compare it with the simulation results. This is likely to reveal many mysteries regarding the universe, such as the formation of galaxies and dark matter.
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【▲ Rewinding a snapshot of the virtual universe in a simulation. It reveals how it grew into the large-scale structure of the universe. ]
（Credit: NASA’s Goddard Space Flight Center/A. Yung）
“Given the panoramic view of the early universe[with the wide-field survey capabilities of the Roman Space Telescope],” Yung said, “obtained through the ‘eye of a needle’ by the Hubble Space Telescope and the James Webb Space Telescope. “It will help us understand how well the snapshots correspond to what the early universe looked like at the time[as revealed by the Roman Space Telescope].”
Related: Investigating a method to approach the origin of “large-scale structure of the universe” by “rewinding” the effects of gravitational interactions
Source
Text / Misato Kadono
