A research group led by Assistant Professor Chiaki Hikage of the University of Tokyo created and analyzed the deepest (past universe) and wide heavenly map of the spatial distribution of 3D dark matter in the universe by the Subaru Telescope.The group also includes the National Astronomical Observatory of Japan, Nagoya University, Princeton University in the United States, Carnegie Mellon University in the United States, and the Institute of Astronomical and Astronomical Physics, Taiwan Central Research Institute.
Dark matter is an unknown substance that is not an atom and occupies more than 80% of the universe, and is said to play a role in the formation of the structure of the universe.The phenomenon that the orbit of light is bent by the gravity of this dark matter is called the gravity lens effect, and when light passes through a region with strong gravity such as a galaxy or a group of galaxies, the shape of the galaxy is observed to be distorted by the effect.Of these, the one with a small degree of distortion is called the weak gravitational lens effect, which makes a map of the dark matter of the universe and allows us to know the formation process of the structure of the universe.
The Subaru Telescope is the main optical telescope of the National Astronomical Observatory of Japan installed on the summit of Mauna Kea in Hawaii. In 2012, the world's highest-performance large-scale wide-field digital camera "Hyper Supreme Cam (HSC)" was installed at the main focus of the telescope.This research is the first result of this HSC's theory of precision cosmology.
This time, we succeeded in observing the gravitational lens distortion effect in the shape of about 1000 million galaxies, and accurately measured the physical quantities that represent the degree of formation of the structure of the universe such as galaxies.Combined with this result and the results of the European Space Agency's (ESA) space background radiation observation satellite Planck and other space observations, we can find out about the nature of dark energy (energy that accelerates the expansion of the universe), which is the biggest mystery of the universe. Obtained.The results of this HSC use only about 10% of the data of the entire plan, and it is expected that further elucidation of space models and dark matter will be made in the future.
Paper information:Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
* The results of this research were published on the preprint server (https://arxiv.org/abs/2018) on September 9, 26, and were published in the Publications of the Astronomical Society of Japan (PASJ). Posted and peer-reviewed
