Astrophysicists uncover the reason behind the absence of spiral galaxies in our supergalactic plane

Evolution of galaxies in dense star clusters

In dense galaxy clusters in supergalactic planes, galaxies frequently experience interactions and mergers with other galaxies. This transforms the spiral galaxy into an elliptical galaxy (a smooth galaxy with no obvious internal structure or spiral arms), leading to the growth of a supermassive black hole.

In contrast, away from the plane, galaxies can evolve in relative isolation, which helps maintain their spiral structure.

Innovative simulations and important discoveries

Research results will be published in a magazine natural astronomy.

The Milky Way is part of a supergalactic plane that includes several giant galaxy clusters and thousands of individual galaxies. Most of the galaxies found here are elliptical galaxies.

The research team used the SIBELIUS (Simulations Beyond the Local Universe) supercomputer simulation, which tracks the evolution of the universe over 13.8 billion years, from the beginning of the universe to the present.

Distribution of the brightest galaxies in the local universe. observed in the 2MASS survey (left panel) and reproduced in the SIBELIUS simulation (right panel). Both panels show projections in supergalactic coordinates down to about 100 megaparsecs (Mpc). The nearly vertical stripes of the sky represent the region of the sky hidden behind our Milky Way galaxy. The simulation accurately reproduces the structure seen in the local universe.Credit: Dr. Thiru Sawala

While most cosmological simulations consider random patches of the universe and cannot be directly compared to observations, SIBELIUS aims to accurately reproduce observed structures, including supergalactic planes. . The final simulation is in remarkable agreement with telescopic observations of the universe.

Contribution and significance of research

Study co-author Professor Carlos Frenk, Ogden Professor of Fundamental Physics at Durham University’s Institute of Computational Cosmology, said:

“This is rare, but not a complete anomaly. Our simulations reveal details of galaxy formation, such as the change from spirals to ellipses due to galaxy mergers.”

“Furthermore, the simulations show that the Standard Model of the Universe, which is based on the idea that most of the mass of the Universe is cold dark matter, is one of the most remarkable structures in the Universe, including the magnificent structure of which the Milky Way Galaxy forms part. This shows that the structure can be reproduced.”

The unusual separation of spiral and elliptical galaxies in the local universe has been known since the 1960s and was included in a recent list of “cosmic anomalies” compiled by renowned cosmologist and 2019 Nobel Prize winner Professor Jim Peebles. prominently mentioned.

Study lead author Dr Thiru Sawala, a postdoctoral fellow at Durham University and the University of Helsinki, said: lecture.

“Then we realized that simulations had already been completed that might contain the answer. Our research shows that the known mechanisms of galaxy evolution also work in this unique cosmic environment. Masu.”

Reference: “A distinct distribution of elliptical and disk galaxies across local superclusters as a ΛCDM prediction” by Til Sawalha, Carlos Frenk, Jens Jachet, Peter H. Johansson, and Guillem Laveau, 2023. 11 20th of the month, natural astronomy.
DOI: 10.1038/s41550-023-02130-6

The supercomputer simulations were run on the Cosmology Machine (COSMA 8) supercomputer hosted by Durham University’s Institute for Computational Cosmology on behalf of the UK’s DiRAC high-performance computing facility, and on CSC’s Mahti supercomputer in Finland. .

This research was funded by the European Research Council, the Academy of Finland, and the UK Science and Technology Facilities Council.