Related Experiment Video
Updated: Jun 10, 2026

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown
Published on: February 14, 2014
An intensity map of hydrogen 21-cm emission at redshift z approximately 0.8
Tzu-Ching Chang1, Ue-Li Pen, Kevin Bandura
1IAA, Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan. tchang@cita.utoronto.ca
Abstract:
Observations of 21-cm radio emission by neutral hydrogen at redshifts z approximately 0.5 to approximately 2.5 are expected to provide a sensitive probe of cosmic dark energy. This is particularly true around the onset of acceleration at z approximately 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 approximately 4sigma.
Related Concept Videos
Emission Spectra
IR Spectrum Peak Broadening: Hydrogen Bonding
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
IR Spectrum Peak Intensity: Dipole Moment
Intensity Of Electromagnetic Waves
Proton (¹H) NMR: Chemical Shift
Absorption signals of all the protium nuclei in a...
Atomic Emission Spectroscopy: Overview

