2022/01/15 by Pierre-Henri Chavanis, Chavanis, Pierre-Henri · 2 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Scientific Research and Discoveries
paper · pdf · doi:10.48550/arxiv.2201.05903
openalex publication_date 2022/01/15 · openalex created_date 2022/04/03 · openalex updated_date 2026/07/28
The logotropic model [P.H. Chavanis, Eur. Phys. J. Plus \bf 130, 130 (2015)] may be an interesting alternative to the ΛCDM model. It is able to account for the present accelerating expansion of the universe while solving at the same time the core-cusp problem of the CDM model. In the logotropic model, there is a single dark fluid. Its rest-mass plays the role of dark matter and its internal energy plays the role of dark energy. We highlight two remarkable predictions of the logotropic model. It yields cored dark matter halos with a universal surface density equal to Σ0\rm th=0.01955 c√Λ/G=133 M\odot/\rm pc2 without free parameter in very good agreement with the observational value Σ0\rm obs=141-52+83 M\odot/\rm pc2. It also predicts the present ratio of dark energy and dark matter to be the pure number Ω\rm de,0\rm th/Ω\rm dm,0\rm th=e=2.71828... in very good agreement with the observations giving Ω\rm de,0\rm obs/Ω\rm dm,0\rm obs=2.669± 0.08. Using the measured present proportion of baryonic matter Ω\rm b,0\rm obs=0.0486± 0.0010, we find that the values of the present proportion of dark matter and dark energy are Ω\rm dm,0\rm th=(1)/(1+e)(1-Ω\rm b,0)=0.2559 and Ω\rm de,0\rm th=(e)/(1+e)(1-Ω\rm b,0)=0.6955 in very good agreement with the observational values Ω\rm dm,0\rm obs=0.2589± 0.0057 and Ω\rm de,0\rm obs=0.6911± 0.0062 within the error bars. These theoretical predictions are obtained by advocating a mysterious strong cosmic coincidence (dubbed "dark magic") implying that our epoch plays a particular role in the history of the universe.