We explore the prospects of using the hyperfine transition of 3He+ as a probe of the intergalactic medium. The emission signal from ionized regions during reionization is expected to be anti-correlated with 21cm maps. The predicted emission signal from Lyman-alpha blobs at lower redshifts is detectable with future radio observatories.
@article{arxiv.0905.1698,
title = {The hyperfine transition of 3He+ as a probe of the intergalactic medium},
author = {J. S. Bagla and Abraham Loeb},
journal= {arXiv preprint arXiv:0905.1698},
year = {2009}
}