https://doi.org/10.1140/epjc/s10052-024-12948-7
Regular Article - Theoretical Physics
Cosmological evolution of matter with interacting dust fluids
1
Physics Department, University of Nairobi, P. O. Box 30197-00100 GPO, Nairobi, Kenya
2
Physics Department, University of the Witwatersrand, 1 Jan Smuts Avenue, 2000, Johannesburg, South Africa
3
Department of Physics and Astronomy, University of the Western Cape, 7535, Cape Town, South Africa
Received:
7
March
2024
Accepted:
21
May
2024
Published online:
5
June
2024
We split the total matter fluid into a bound (halo) component and an unbound (free particles) fluid component that is accreted by the halos. We adopt a different framework that treats the structure formation problem as a gravitational interaction between these virialised cold dark matter halos and the unbound inter-halo cold dark matter (and cold baryon) particles. This interaction involves in general an exchange of energy and momentum during the accretion process. We then explore the evolution of the average matter density and of large-scale structure formation, using a simplified phenomenological model that is based on results from extended Press–Schechter and N-body simulations. At high redshifts most matter is in diffuse form and is not part of the halos. As particles are accreted by the virialised halos, the particle number density decreases and that of the bound matter increases. We also present a general analysis of the background and linear perturbations for the interacting fluids, showing in detail the energy and momentum exchange terms.
© The Author(s) 2024
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3.
