Hydrogen 21-cm Intensity Mapping at redshift 0.8
Abstract
Observations of 21-cm radio emission by neutral hydrogen at redshifts z ~ 0.5 to ~ 2.5 are expected to provide a sensitive probe of cosmic dark energy. This is particularly true around the onset of acceleration at z ~ 1, where traditional optical cosmology becomes very difficult because of the infrared opacity of the atmosphere. Hitherto, 21-cm emission has been detected only to z=0.24. More distant galaxies generally are too faint for individual detections but it is possible to measure the aggregate emission from many unresolved galaxies in the 'cosmic web'. Here we report a three dimensional 21-cm intensity field at z=0.53 to 1.12. We then co-add HI emission from the volumes surrounding about ten thousand galaxies (from the DEEP2 optical galaxy redshift survey. We detect the aggregate 21-cm glow at a significance of ~ 4 sigma.
Cite
@article{arxiv.1007.3709,
title = {Hydrogen 21-cm Intensity Mapping at redshift 0.8},
author = {Tzu-Ching Chang and Ue-Li Pen and Kevin Bandura and Jeffrey B. Peterson},
journal= {arXiv preprint arXiv:1007.3709},
year = {2010}
}
Comments
18 pages, 2 figures, including Supplementary Information. To appear in Nature, July 22, 2010 issue