| Precise if your presentation is oral or a poster : | Poster |
| Title of your presentation : | Cosmological Cosmic Ray Production of Beryllium and Boron |
| Abstract |
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The abundance of 6Li in Population II stars of the galactic halo has been observed at a thousand times the predicted primordial value. Cosmological cosmic rays (CCRs) induced production of 6Li, which depends on the escape efficiency of CCRs from the structures, can account for this high value. In this context, we calculate the non-thermal evolution with redshift of D, Be, and B in the intergalactic medium (IGM). We take into account direct production in the IGM by pHe and CNO CCRs impinging on the intergalactic gas (CNO contribution is dominant). Neutrino spallation and low-energy production within the structures (later ejected by outflows to the IGM) are always sub-dominant. We find that: 1. Deuterium production is negligible compared to the BBN abundance; 2. A potentially detectable Be and B initial enrichment, coherent with the observed stars in the galactic halo, is produced by these processes at the time of the formation of the Galaxy (z~3); 3. The associated CCR-induced extragalactic gamma-ray background is found to be well below existing data. This study will be updated from new constraints of Pop III stars (see E. Rollinde et al arXiv:0806.2663). |
