Astronomy and Astrophysics – Astrophysics
Scientific paper
2000-03-13
Astronomy and Astrophysics
Astrophysics
12 pages including one figure, uses aaspp4, submitted to ApJ
Scientific paper
10.1086/317197
Many lines of evidence suggest that nonbaryonic dark matter constitutes roughly 30% of the critical closure density, but the composition of this dark matter is unknown. One class of candidates for the dark matter is compact objects formed in the early universe, with typical masses M between 0.1 and 1 solar masses to correspond to the mass scale of objects found with microlensing observing projects. Specific candidates of this type include black holes formed at the epoch of the QCD phase transition, quark stars, and boson stars. Here we show that accretion onto these objects produces substantial ionization in the early universe, with an optical depth to Thomson scattering out to z=1100 of approximately tau=2-4 [f_CO\epsilon_{-1}(M/Msun)]^{1/2} (H_0/65)^{-1}, where \epsilon_{-1} is the accretion efficiency \epsilon\equiv L/{\dot M}c^2 divided by 0.1 and f_CO is the fraction of matter in the compact objects. The current upper limit to the scattering optical depth, based on the anisotropy of the microwave background, is approximately 0.4. Therefore, if accretion onto these objects is relatively efficient, they cannot be the main component of nonbaryonic dark matter.
No associations
LandOfFree
Reionization Constraints on the Contribution of Primordial Compact Objects to Dark Matter does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Reionization Constraints on the Contribution of Primordial Compact Objects to Dark Matter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reionization Constraints on the Contribution of Primordial Compact Objects to Dark Matter will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-148743