03-02-2018, 05:05 PM
"Unprecedentedly wide and sharp dark matter map"
This is related to a couple of recent posts, and although I'm not an expert in the field of cosmology, this is a very clever and challenging observation using Hyper Suprime-Cam at Subaru on Mauna Kea. The astronomers used "weak gravitational lensing" to map the distribution of dark matter in a relatively large area. Weak gravitational lensing essentially means they didn't use the gravity of one particular massive galaxy to measure what was behind it. They used the tiny effects of lensing that occur by chance when observing distant objects to map the distribution of dark matter nearer by.
https://phys.org/news/2018-03-unpreceden...-dark.html
"It is important to note that growth rate cannot be probed well if we only observe visible matter (stars and galaxies). This is because we now know that nearly 80 % of the matter is an invisible substance called dark matter. The team adopted the 'weak gravitation lensing technique." The images of distant galaxies are slightly distorted by the gravitational field generated by the foreground dark matter distribution. Analysis of the systematic distortion enables us to reconstruct the foreground dark matter distribution."
This is related to a couple of recent posts, and although I'm not an expert in the field of cosmology, this is a very clever and challenging observation using Hyper Suprime-Cam at Subaru on Mauna Kea. The astronomers used "weak gravitational lensing" to map the distribution of dark matter in a relatively large area. Weak gravitational lensing essentially means they didn't use the gravity of one particular massive galaxy to measure what was behind it. They used the tiny effects of lensing that occur by chance when observing distant objects to map the distribution of dark matter nearer by.
https://phys.org/news/2018-03-unpreceden...-dark.html
"It is important to note that growth rate cannot be probed well if we only observe visible matter (stars and galaxies). This is because we now know that nearly 80 % of the matter is an invisible substance called dark matter. The team adopted the 'weak gravitation lensing technique." The images of distant galaxies are slightly distorted by the gravitational field generated by the foreground dark matter distribution. Analysis of the systematic distortion enables us to reconstruct the foreground dark matter distribution."