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arXiv · 1606.07790

Small scale problems of the $Λ$CDM model: a short review

Antonino Del Popolo·Morgan Le Delliou
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Abstract

The $Λ$CDM model, or concordance cosmology, as it is often called, is a paradigm at its maturity. It is clearly able to describe the universe at large scale, even if some issues remain open, such as the cosmological constant problem , the small-scale problems in galaxy formation, or the unexplained anomalies in the CMB. $Λ$CDM clearly shows difficulty at small scales, which could be related to our scant understanding, from the nature of dark matter to that of gravity; or to the role of baryon physics, which is not well understood and implemented in simulation codes or in semi-analytic models. At this stage, it is of fundamental importance to understand whether the problems encountered by the $Λ$DCM model are a sign of its limits or a sign of our failures in getting the finer details right. In the present paper, we will review the small-scale problems of the $Λ$CDM model, and we will discuss the proposed solutions and to what extent they are able to give us a theory accurately describing the phenomena in the complete range of scale of the observed universe.

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Antonino Del Popolo, Morgan Le Delliou. 2017-03-23. Small scale problems of the $Λ$CDM model: a short review. https://doi.org/10.3390/galaxies5010017

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