Correcting correlation functions for redshift-dependent interloper contamination

Understand

The construction of catalogues of a particular type of galaxy can be complicated by interlopers contaminating the sample.

• In spectroscopic galaxy surveys this can be due to the misclassification of an emission line; for example in the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) low redshift [OII] emitters may make up a few percent of the observed Ly${\alpha}$ emitter (LAE) sample.
• The presence of contaminants affects the measured correlation functions and power spectra.
• Previous attempts to deal with this using the cross-correlation function have assumed sources at a fixed redshift, or not modelled evolution within the adopted redshift bins.