A wide and sharp 3D dark matter map based on the recent imaging data by Hyper Suprime-Cam (HSC) on the Subaru Telescope has been released by an international team of astronomers including the National Astronomical Observatory of Japan and University of Tokyo.
The camera, called Hyper Suprime-Cam captures a wide area in the sky equivalent to the combined size of nine full moons in one shot.
Dark matter is the most mysterious building block of outer space and it is believed to form a fundamental part of our universe.
Hyper Suprime-Cam image of a location with a highly significant dark matter halo detected through the weak gravitational lensing technique. This halo is so massive that some of the background (blue) galaxies are stretched tangentially around the center of the halo. This is called strong lensing. Credit: NAOJ
This is only 11 % of the planned final map, but it is already unprecedentedly wide. It is an important step to better understanding the Universe’s accelerating expansion.
The dark matter distribution is estimated by the weak gravitational lensing technique. The team located the positions and lensing signals of the dark matter halos and found indications that the number of halos could be inconsistent with what the simplest cosmological model suggests.
For now, this is the best and the sharpest dark matter map covering such a wide area. It covers a wider area and features a higher resolution than any other similar maps, according to researchers.
In the 1930’s, Edwin Hubble and his colleagues discovered the expansion of the Universe. A formula relating matter and the geometry of space-time was required in order to express the expansion of the Universe mathematically.
Coincidentally, Einstein had already developed just such a formula. Modern cosmology is based on Einstein’s theory for gravity.
Deeper understanding of the distribution of dark matter would help check the validity of the theory that the expansion of the universe is speeding up. Study on dark matter would also help understand better how galaxies and galaxy clusters have been formed.