TITLE:
Ionizing radiation from hydrogen recombination strongly suppresses the lithium scattering signature in the CMB.
AUTHOR(S):
Eric R. Switzer and Christopher M. Hirata (Princeton Univ.).
DATE:
2005 Jul 05 (arXiv, v1, posted); 2005 Jul 06 (Phys. Rev. D, submitted); 2005 Oct 07 (Phys. Rev. D, published).
AVAILABILITY:
arXiv astro-ph/0507106 (free).
APS (requires subscription).
PUBLICATION INFORMATION: Physical Review D, 72, 083002 (9 pages).
ABSTRACT:
It has been suggested that secondary CMB anisotropies generated by neutral lithium could open a new observational window into the
universe around the redshift z ~ 400, and permit a determination of the primordial lithium abundance. The effect is due to resonant
scattering in the allowed LiI doublet (2s 2S1/2 -- 2p 2P1/2,3/2), so its observability
depends on the formation history of neutral lithium. Here we show that the ultraviolet photons produced during hydrogen recombination
are sufficient to keep lithium in the LiII ionization stage in the relevant redshift range and suppress the neutral lithium fraction
by ~ 3 orders of magnitude from previous calculations, making the lithium signature unobservable.
ADS BIBLIOGRAPHIC CODE: 2005PhRvD.72h3002S
COMMENTS: N/A.