Abstract
The standard cosmological model with cold dark matter provides an accurate account of the cosmological background and large-scale structures of the Universe, while numerical simulations based on this model successfully reproduce many observed properties of galaxies. However, certain tensions persist between the model and observations, which may indicate its limitations.
In particular, the baryonic Tully-Fisher relation and smaller-scale correlations could indicate a stronger coupling between baryonic matter and gravitational field than predicted by the standard model. In addition, simulations do not agree on the distribution of dark matter within halos, and observations reveal unexpected diversity in galaxy rotation curves, as well as the presence of satellite planes, difficult to explain within the framework of the model. Simulations also struggle to reproduce the abundance of central bars in spiral galaxies, and the gas content of these galaxies.
These challenges could be solved by refining our understanding of galaxy formation and evolution. However, the difficulties encountered may be of a more fundamental nature. Alternatives to cold dark matter, such as warm, fuzzy or self-interacting dark matter, or modifications to gravity, have been proposed in an attempt to resolve these problems. These models offer interesting perspectives, but also raise new questions of their own.
