The Computational Cosmology group of the Department of Astronomy and Astrophysics (DAA) of the University of Valencia has published an article in The Astrophysical Journal Letters, one of the international journals with the greatest impact on Astrophysics, where it demonstrates, through complex theoretical-computational models, that cosmic voids in the universe are constantly being filled with matter from the outside.

“This totally unexpected result may have far-reaching implications, not only in our understanding of the large-scale structure of the universe, but also in the scenarios of formation and evolution of galaxies”, explained Vicent Quilis, director of the Department of Astronomy and Astrophysics from the University of Valencia and principal investigator of the project.

“Cosmic voids are the largest structures that exist in the cosmos, and knowledge of their formation and evolution is crucial to understanding the structure of the universe”, says Susana Planelles, co-director of the research. Precisely for being huge volumes with a very low material content, their study as a physical setting has always been tremendously complex. From the observational point of view, the analysis of the few objects existing inside them is very difficult and the theoretical modelling of these scenarios is no less complex, for which very simplified descriptions of these structures are used.

The commonly accepted paradigm among the scientific community understood cosmic voids as fossil regions derived from the smooth and slow evolution of the less dense regions generated in the primordial phases of the universe. “In this way, the voids would expand, increasing their volume and losing their matter, which would escape through their borders. In this scenario, the Universe would be formed by large bubbles with practically no content (the voids) that when expanding would push matter between them, which would give rise to filaments and clusters of galaxies”, explains David Vallés, first signatory of the publication.

However, this firmly established idea has been challenged by the work carried out by the DAA of the University of Valencia with a pioneering research that is part of the doctoral thesis project of researcher David Vallés and has been directed by the professor of the Department of Astronomy and Astrophysics Susana Planelles and by Professor Vicent Quilis. The complex cosmological simulations required have been carried out on the University of Valencia’s supercomputer, “Lluís Vives”.

Article: David Vallés-Pérez et al 2021 ApJL 920 L2. DOI: https://doi.org/10.3847/2041-8213/ac2816

Picture from the news: Three-dimensional representation of a volume of the universe in which we can see how the distribution of matter formed by filaments and clusters of galaxies (in blue and green) surrounds a cosmic void (in red). The black arrows illustrate a flow of matter entering the void from the surrounding environment.