2001/04/30 by Craig J. Hogan · 2 citations
Physics and Astronomy · #Annihilation #Annihilation radiation #Astrophysics #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Dark matter halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Nuclear physics #Particle (ecology) #Physics #Positron #Positron annihilation #astro-ph
paper · pdf · doi:10.1103/physrevd.64.063515
published as Phys.Rev. D64 (2001) 063515 · 8 pages, 2 figures, Latex, revised version submitted to Phys. Rev. D with more detailed explanation and new references added
arxiv created 2001/05/30 · openalex publication_date 2001/08/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Cold primordial particle dark matter forms with a distribution in six-dimensional phase space closely approximating a three-dimensional sheet. Folds in the mapping of this sheet onto configuration space create ubiquitous sheetlike caustics (``micropancakes''). A typical weakly interacting massive particle dark matter halo has many micropancakes, each with a scale comparable to the halo itself, a width about 10^\ensuremath-8 of the halo size and a typical maximum density up to about 104 times the halo mean. It is suggested here that the total annihilation rate of dark matter particles is dominated by particles close to these micropancakes, so radiation is emitted predominantly from highly contorted two-dimensional surfaces rather than a filled volume. The total annihilation rate of particles is about a factor of 5 higher than predicted from N-body simulations, which cannot resolve these features. Micropancakes also produce sharp line discontinuities in the surface brightness of annihilation radiation.