Why is going to space crucial to map dark matter?

A key promise of the Euclid mission is to explore the evolution of the dark Universe. The foundation of this ambitious program is a large optical and near-infrared imaging survey. Euclid’s cosmic map will depict more than one billion galaxies out to 10 billion light-years, making it the biggest and most detailed cosmological data set of our age. How does the quality of the first Euclid images compare to another reference cosmological data set, the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Survey?

What’s in Euclid’s First Light images?

Euclid’s “First Light” engineering images show a lot of things. There are obviously some astronomical objects, but also some stranger features that are not. The reason is that these images are “raw”, they have not been digitally treated the ways as needs to be done to create science-ready images. They contain a lot of features that are properties of the detectors used, but also unwanted internal reflections of the optics, as well as cosmic rays that hit all space telescopes. Converting these images into science-ready data is the task of the Euclid Science Ground Segment, which has developed a huge and very detailed data treatment (“data reduction”) pipeline over many years.

Red Book cover, detail

Publication: Euclid “Red Book” passes 2500 citation mark

Currently it is the most comprehensive summary of Euclid’s mission goals, its technology and science: the “Euclid Definition Study Report“, aka The Euclid Red Book. This 116 page ESA report from 2011 concludes Euclid’s initial design phase and describes Euclid at the point of adoption as a mission by ESA.

Scroll to Top