Empowering line intensity mapping to study early galaxies

Understand

Line intensity mapping is a superb tool to study the collective radiation from early galaxies.

• However, the method is hampered by the presence of strong foregrounds, mostly produced by low-redshift interloping lines.
• We present here a general method to overcome this problem which is robust against foreground residual noise and based on the cross-correlation function $\psi_{\alpha L}(r)$ between diffuse line emission and Ly$\alpha$ emitters (LAE).
• We compute the diffuse line (Ly$\alpha$ is used as an example) emission from galaxies in a $(800{\rm Mpc})^3$ box at $z = 5.7$ and $6.6$.