Interpreting the unresolved intensity of cosmologically redshifted line radiation

Understand

Intensity mapping experiments survey the spectrum of diffuse line radiation rather than detect individual objects at high signal-to-noise.

• Spectral maps of unresolved atomic and molecular line radiation contain three-dimensional information about the density and environments of emitting gas, and efficiently probe cosmological volumes out to high redshift.
• Intensity mapping survey volumes also contain all other sources of radiation at the frequencies of interest.
• Continuum foregrounds are typically ~10^2-10^3 times brighter than the cosmological signal.