Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-10-19
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
14 pages, 11 figure, submitted to MNRAS
Scientific paper
In this paper we explore the potential effects of DM annihilations on the cosmological recombination spectrum. With this example we want to demonstrate that the cosmological recombination spectrum in principle is sensitive to details related to possible extra energy release during recombination. We restrict ourselves to DM models which produce a negligible primordial distortion of the CMB energy spectrum. However, since during the epoch of cosmological recombination a large fraction of the deposited energy can directly go into ionizations and excitations of neutral atoms, both the cosmological recombination spectrum and ionization history can still be affected significantly. We compute the modifications to the cosmological recombination spectrum using our multi-level HI and HeI recombination code, showing that additional photons are created due to uncompensated loops of transitions which are induced by DM annihilations. As we illustrate here, the results depend on the detailed branching of the deposited energy into heating, ionizations and excitations. This dependence in principle should allow us to shed light on the nature of the underlying annihilating DM model (or more generally speaking, the mechanism leading to energy injection) when measuring the cosmological recombination spectrum. However, for current upper limits on the potential DM annihilation rate during recombination the cosmological recombination spectrum is only affected at the level of a few percent. Nevertheless, we argue here that the cosmological recombination spectrum would provide another independent and very direct way of checking for the presence of sources of extra ionizing or exciting photons at high redshifts. This would open an new window to possible (non-standard) processes occurring (abridged)
No associations
LandOfFree
Could the Cosmological Recombination Spectrum Help Us Understand Annihilating 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 Could the Cosmological Recombination Spectrum Help Us Understand Annihilating Dark Matter?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Could the Cosmological Recombination Spectrum Help Us Understand Annihilating Dark Matter? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-716641