1998/05/04 by Neil J. Cornish, Glenn D. Starkman, Cornish, Neil J. +1
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Astrophysics (astro-ph) #FOS: Physical sciences #Quantum Mechanics and Applications #Relativity and Gravitational Theory #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9805027
3 pages, no figures, gzipped postscript
arxiv created 1998/05/04 · openalex publication_date 1998/05/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The case grows ever stronger that the average density of matter, ordinary and dark, is less than the critical density required for a flat universe. However, most of determinations of the mass density have been dynamical, hence sensitive only to matter which is clustered at or below the scale of the observed dynamical systems. The density may still be critical if there is a dark matter component which is relatively smooth on the scales of galaxies or clusters. Thoughts on this matter have focused on the possibility of an effective cosmological constant or vacuum energy. In this letter we examine an alternative possibility - that there is a second component to the dark matter which has a repulsive self-interaction. We show that given even very weak self-repulsion, this dark matter would remain unclustered. While this repulsive alternative is perhaps aptly named, it is arguably at least as palatable as a cosmological constant.