Light in the dark - Galaxies enriching MultiDark universe

20 November 2017. Scientists from the Leibniz Institute for Astrophysics Potsdam (AIP) have joined an international research team to create one of the largest sets of galaxies in a computer generated universe. The data are published via AIP's CosmoSim database.
Light in the dark - Galaxies enriching MultiDark universe

Visualization of the model galaxies. Credit: Kristin Riebe/AIP

The Universe is filled with an immeasurable number of galaxies that themselves are accumulations of billions of stars. Understanding how these 'islands in the universe’ formed and evolved and how they are distributed throughout the Universe is central to the field of Cosmology. Luckily, we now live in an era where both ground- and space-based telescopes are being designed to study the Universe out to unprecedented distances, peering back billions of years to when the Universe was an infant. But the interpretation of these data requires theoretical models. As such, astronomers generate model universes, where galaxies are simulated, which may act as a test bed for the assessment of theories. However, such virtual universes are computationally expensive, numerically challenging, and often lack the sheer number and details of the galaxies we observe.


Now, an international team led by Prof. Alexander Knebe from the Universidad Autónoma de Madrid and Prof. Francisco Prada from the Instituto de Astrofísica de Andalucía (bringing together experts from South America, the USA, Europe, and Australia) has created one of the largest publicly available virtual universes, known as the “MultiDark-Galaxies”. What is provided to the community are galaxy catalogues based upon three distinct models that all include the physical processes relevant for galaxy formation and evolution, conforming to and reproducing specific empirical observations.


All galaxy data and also data for the simulation itself is available via the database, hosted at the Leibniz-Institut for Astrophysics Potsdam in Germany. A selected subset is also available at, hosted at NMSU in the US and the Instituto de Astrofísica de Ansalucía CSIC in Spain. The more than 100 million virtual galaxies per model cover a cosmological volume comparable to that probed by on-going and future observational campaigns. They therefore equip researchers in the field with an unparalleled opportunity to better understand existing observations and to even make predictions for upcoming missions. More information can be found in the accompanying paper that has just been accepted by MNRAS and can be found on the arXiv: 1710.08150


Visualization of the model galaxies. The left panel shows a slice of thickness 4.7 million light years through the whole simulation that itself has a side length of 4.8 billion light years. Each galaxy is represented by a yellow dot; the background indicates the underlying dark matter density. The right panel zooms into a smaller region. Here the dark matter haloes hosting the galaxies are visible as circles, colour-coded according to the projected density. Their sizes are scaled with their masses. Credit: Kristin Riebe/AIP


Original press release by Universidad Autónoma Madrid:

More information about MultiDark:

More information about CosmoSim database:

Science contact:
Noam Libeskind, +49 331-7499 641,


Media contact:
Katrin Albaum, +49 331-7499 803,


Database contacts:
Kristin Riebe, +49 331-7499 377,
Anastasia Galkin +49 331-7499 685,
Harry Enke, +49 331-7499 433,


The CosmoSim database is a service by the Leibniz-Institute for Astrophysics Potsdam (AIP). It contains public data from cosmological simulations of different sizes and resolutions. The data can be accessed via a web interface and Virtual Observatory tools.


The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.