Molecular line emission of RW Aur B. In the top is the original continuum subtracted spectra, with the same continuum subtraction algorithm used for the primary disks. In the middle is the spectra after filtering the signals with frequency smaller than than 0.5 px⁻¹. In the bottom, the spectra after frequency filtering and subtracting a masked average with a window size of 10 px. For reference, slab models for HCN, H₂O, and CO₂, are shown with the original and with the modified spectra.