Cosmological Constraints from the First-Year Subaru Hyper Suprime-Cam Survey

[Summary]

Using the powerful Japanese Subaru telescope, the Hyper Suprime-Cam (HSC) survey collaboration team has made and analyzed the deepest wide field map of the three-dimensional distribution of matter in the Universe. Led by Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Project Assistant Professor Chiaki Hikage, a team of scientists primarily from Japan, Taiwan and Princeton University has used the gravitational distortion of images of about 10 million galaxies to make a precise measurement of the lumpiness of matter in the Universe. By combining this measurement with the European Space Agency Planck satellite’s observations of the cosmic microwave background, and other cosmological experiments, the team has been able to further constrain the properties of the “dark energy” that dominates the energy density of the Universe. (September 26, 2018 press release)



Figure 1:Left panel: The 3-dimensional dark matter map of the Universe inferred from one of the six HSC observation areas is shown in the background with various shades of blue (brighter areas have more dark matter). The map was inferred from the distortions of shapes of galaxies in the HSC data which are indicated by white sticks. The stick lengths represent the amount of distortion and the angle of the stick corresponds to the direction of the distortion. Right panel: The measurements are enabled by the light from distant galaxies that travels through the Universe and gets deflected by matter at different epochs in the Universe, before reaching the Subaru telescope. (Credit: HSC project/UTokyo)



Figure 3:The cosmological constraints on the fractional contribution of matter to the energy budget of the Universe (rest of it corresponds to dark energy), and the clumpiness of the matter distribution today (S8), as inferred from the analysis of the 3d dark matter map. The results of the clumpiness of the matter distribution from HSC observations of the distant Universe using weak gravitational lensing are consistent with results from other similar observations (Dark Energy Survey and the Kilo Degree Survey) of slightly nearby Universe. The results from the cosmic microwave background observations during the Universe’s infancy obtained by the Planck satellite are shown in blue. (Credit: HSC Project)

See the full story: Kavli IPMU press release "Cosmological constraints from the first-year Subaru Hyper Suprime-Cam survey"

[Computers]

In this research, "PC Cluster" and Supercomputer "ATERUI" operated by CfCA were used for estimations of various model parameters including clumpiness of the matter distribution S8 from comparisons observation results and cosmological simulations.
"PC Cluster" (upper panel) is the system for small-scale and non-parallel simulations. This system consists of 224 nodes as of October 2018.
"ATERUI" (lower panel) is NAOJ's 4th generation supercomputer dedicated for astronomical simulations. The theoretical peak performance is 1.058 Pflops. This system had been operated until March 2018.


[Preprint Manuscript]

Title: Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
Authors: Chiaki Hikage, Masamune Oguri, Takashi Hamana, Surhud More, Rachel Mandelbaum, Masahiro Takada, et al.
arXiv: 1809.09148

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[Related Links]

Kavli IPMU press release "Cosmological constraints from the first-year Subaru Hyper Suprime-Cam survey"
Subaru Telescope press release "Cosmological Constraints from the First-Year Hyper Suprime-Cam"
NAOJ press release "Cosmological Constraints from the First-Year Hyper Suprime-Cam"

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