Research @ KICP
October 20, 2004
Sloan Digital Sky Survey uses gravitational lensing to compare the distributions
by Erin Sheldon
Gravitational lensing offers a new probe of Dark Matter: the light from distant galaxies is bent by the gravity of foreground halos, distorting the galaxy images. KICP members Erin Sheldon and Joshua Frieman and their collaborators on the SDSS team used the shapes of 8 million galaxies to show that galaxies trace the dark matter on large scales, consistent with the Universe containing 30% Dark Matter, 70% Dark Energy.
The graph shows the measurement of the galaxy-mass correlation function (points) from weak lensing, compared with the galaxy-galaxy correlation function (solid curve) from the Sloan Digital Sky Survey (upper panel). Lower panel shows the ratio of these two, which constrains the relation between the dark and luminous matter distributions as well as the mean density of the Universe.