On Removing Interloper Contamination from Intensity Mapping Power Spectrum Measurements

Understand

Line intensity mapping experiments seek to trace large scale structure by measuring the spatial fluctuations in the combined emission, in some convenient spectral line, from individually unresolved galaxies.

• An important systematic concern for these surveys is line confusion from foreground or background galaxies emitting in other lines that happen to lie at the same observed frequency as the "target" emission line of interest.
• We develop an approach to separate this "interloper" emission at the power spectrum level.
• If one adopts the redshift of the target emission line in mapping from observed frequency and angle on the sky to co-moving units, the interloper emission is mapped to the wrong co-moving coordinates.