Cosmology with intensity mapping techniques using atomic and molecular lines

TL;DR

This paper systematically evaluates atomic and molecular emission lines for intensity mapping to enhance cosmological studies of the post-reionization universe, identifying promising lines and experimental prospects.

Contribution

It identifies the most promising emission lines for intensity mapping and assesses their detectability with current and future experiments.

Findings

Lyα intensity mapping feasible at z=2-3 with HETDEX

Far-infrared lines require new dedicated experiments

SPHEREx can study matter distribution using OII and Hα at z=1-4

Abstract

We present a systematic study of the intensity mapping technique using updated models for the different emission lines from galaxies and identify which ones are more promising for cosmological studies of the post reionization epoch. We consider the emission of ${\rm Ly\alpha}$, ${\rm H\alpha}$, H$\beta$, optical and infrared oxygen lines, nitrogen lines, CII and the CO rotational lines. We then identify that ${\rm Ly\alpha}$, ${\rm H\alpha}$, OII, CII and the lowest rotational CO lines are the best candidates to be used as IM probes. These lines form a complementary set of probes of the galaxies emission spectra. We then use reasonable experimental setups from current, planned or proposed experiments to access the detectability of the power spectrum of each emission line. Intensity mapping of ${\rm Ly\alpha}$ emission from $z=2$ to 3 will be possible in the near future with HETDEX, while far-infrared lines require new dedicated experiments. We also show that the proposed SPHEREx satellite can use OII and ${\rm H\alpha}$ IM to study the large-scale distribution of matter in intermediate redshifts of 1 to 4. We found that submilimeter experiments with bolometers can have similar performances at intermediate redshifts using CII and CO(3-2).