Warm Dark Matter: Clues to Primordial Phase Density from the Structure of Galaxy Halos
| dc.creator | Hogan, Craig J. | |
| dc.date | 1999-12-29 | |
| dc.date.accessioned | 2026-07-07T02:35:15Z | |
| dc.date.available | 2026-07-07T02:35:15Z | |
| dc.description | The Cold Dark Matter paradigm successfully explains many phenomena on scales larger than galaxies, but seems to predict galaxy halos which are more centrally concentrated and have a lumpier substructure than observed. Endowing cosmic dark matter with a small primordial velocity dispersion preserves the successful predictions of the Cold Dark Matter scenario on large scales and improves the agreement with halo structure. A ``phase density'' $Q$, proportional to the inverse entropy for nonrelativistic matter, is estimated for relativistically decoupled thermal or degenerate relic particles of mass $m_X$, with a numerical factor depending on the particle type but no cosmological parameters. Since $Q$ cannot increase for dissipationless, collisionless matter, at a given velocity dispersion there is a maximum space density; this ``phase packing'' constraint eliminates the singular density predicted by CDM. The core radius and halo circular velocity scale analogously to degenerate dwarf stars. Particle velocities also filter primordial perturbations on a scale depending on $Q$ and on details of particle distributions. Particle candidates for warm matter are briefly discussed; for warm thermal relics to have the observed mass density requires decoupling prior to the QCD epoch and therefore a superweak interaction with thermal Standard Model particles. | |
| dc.description | 9 pages, Latex, to appear in the Proceedings of the NATO Advanced Study Institute on Astrofundamental Physics, ed. N. Sanchez and A. Zichichi | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9912549 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9912549 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/15542 | |
| dc.subject | Astrophysics | |
| dc.title | Warm Dark Matter: Clues to Primordial Phase Density from the Structure of Galaxy Halos | |
| dc.type | text |