An Intensity Map of Hydrogen 21-cm Emission at Redshift z ~ 0.8
Investigators: Tzu-Ching Chang (Academia Sinica, CITA-Toronto), Ue-Li Pen (CITA-Toronto), Kevin Bandura (Carnegie Mellon Univ), Jeffrey B. Peterson (Carnegie Mellon Univ)
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 neutral-hydrogen (H I) emission from the volumes surrounding about 10,000 galaxies (from the DEEP2 optical galaxy redshift survey). We detect the aggregate 21-cm glow at a significance of ~4σ.
Publication: Nature, 466, 463 (22 July 2010).
