
A Hubble Space Telescope image of the cluster of galaxies Abell 2744 taken in 2014. Over-plotted on the image is the reconstructed map of dark matter shown in blue. The presence and spatial distribution of dark matter is inferred from the light bending it produces. Credit: ESA/Hubble, NASA, HST Frontier Fields and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI). Acknowledgement for overlaid reconstructed dark matter map for Abell2744: Mathilde Jauzac (Durham University, UK and Astrophysics & Cosmology Research Unit, South Africa) and Jean-PaulKneib (École Polytechnique Fédérale de Lausanne, Switzerland).