Through a cosmological supercomputer simulation, an international team of scientists have produced the largest and most accurate virtual representation of our Local Universe to date.
An international team of researchers, including Postdoctoral Researcher Stuart MacAlpine and Professor Peter Johansson from the University of Helsinki, has carried out the largest simulation of the Near Universe, up to a distance of around 600 million light years. This simulation faithfully reproduces the large structures of the universe as they can be seen exactly in the sky up to this distance. This numerical simulation required millions of hours of calculation for the preparation of the initial conditions in France and in the United Kingdom as well as for its execution. The study of this simulation was published in the journal Monthly Notices of the Royal Astronomical Society on December XX, 2021.
Performing a digital simulation of a virtual universe is one of the essential tools for understanding our observed universe. These allow us to test a large number of hypotheses on the impact of different components of the physics of the early universe as well as to verify that the physics of galaxies is well understood. The Sibelius project is a first for building a complete digital replica of our universe, including its particular arrangement as it can be seen in the sky.
The Sibelius project collaboration involved teams in the UK, Sweden, Finland, France and the Netherlands. The construction of the initial conditions, carried out at CINES on French supercomputers, faced particular challenges to both globally and faithfully reproduce up to galaxy group scales the structures visible in the sky. This reproduction includes in particular the Virgo cluster or the Hercules supercluster, but also up to the precise global characteristics of the Milky Way and the Andromeda galaxy, its closest neighbor, as determined using of the Gaia satellite.
In the current paradigm of cosmology, all the structures we observe are the result of small fluctuations in the primordial universe which have been amplified by gravitational instability. These small fluctuations thus lead to a structuring of the universe called "Large Structures" in which galaxies are formed. Modern cosmological simulations successfully reproduce the average properties of these large structures. A big step forward has been taken over the last decade with the construction of statistical methods which also make it possible to obtain the particular distribution of large structures in the sky from small fluctuations hitherto unknown. We therefore now also have access to the history of the formation of these large structures in addition to their currently visible state. It also offers a unique vision on the history of the formation of galaxies in our Local Universe. For example, we can see on the image the exact distribution of the galaxies of the great wall of the CfA survey with the cluster of Berenice's hair as well as that produced by the galaxies in the simulation. In addition to these distant galaxies, the simulation makes it possible to study the formation and the dynamic properties of the local group which includes the Milky Way and the Andromeda galaxy in their environment.
Lead-author Dr. Stuart McAlpine, Postdoctoral researcher at the University of Helsinki, Finland, said:
"This project provides an important bridge between decades of theory and astronomical observations. By simulating our Universe, as we see it, we are one step closer to understanding the nature of our cosmos. These simulations show that the current leading theory of cosmology, the Cold Dark Matter model, can produce all the galaxies we see in our local habitat, an essential benchmark for simulations of this kind to pass."
Lähde:
"SIBELIUS-DARK: a galaxy catalogue of the Local Volume from a constrained realisation simulation", Monthly Notices of the Royal Astronomical Society (MNRAS) xxxx
