Proto-cluster candidates

The Planck all-sky map at submillimetre wavelengths (545 GHz). The band running through the middle corresponds to dust in our Milky Way galaxy. The black dots indicate the location of the proto-cluster candidates identified by Planck and subsequently observed by Herschel. The inset images showcase some of the observations made by Herschel’s SPIRE instrument; the contours represent the density of galaxies.

Full story: Herschel and Planck find missing clue to galaxy cluster formation