Foreground contamination in Ly-alpha intensity mapping during the epoch of reionization

Understand

The intensity mapping of Ly-alpha emission during the epoch of reionization (EoR) will be contaminated by foreground emission lines from lower redshifts.

• We calculate the mean intensity and power spectrum of Ly-alpha emission at z~7, and estimate the uncertainties according to the relevant astrophysical processes.
• We find that the low-redshift emission lines from 6563 A H-alpha, 5007 A [OIII] and 3727 A [OII] will be the strong contaminants on the observed Ly-alpha power spectrum.
• We make use of both the star formation rate (SFR) and luminosity functions (LF) to estimate the mean intensity and power spectra of the three foreground lines at z~0.5 for H-alpha, z~0.9 for [OIII] and z~1.6 for [OII], as they will contaminate the Ly-alpha emission at z~7.