Comparison of a simulated and observed flux emergence region in He I 10 830 Å and He I D₃. Top two rows: He I D₃ images and spectra, and lower two rows: He I 10 830 Å images and spectra. Left column: synthetic data at μ = 1, middle column: synthetic data at μ = 0.27, and right column: observed data at μ = 0.27. The He I D₃ observed image is normalized by the local continuum. The red and blue squares in the images indicate areas over which the spectra are averaged that are displayed in the corresponding color in the panel below the image. The black spectrum is an average over the entire field of view shown in the image. The He I 10 830 Å observed spectral region also contains a Si I line at v_LOS ∼ −85 km s⁻¹ and two telluric lines at v_LOS ∼ 50 km s⁻¹ and v_LOS ∼ 100 km s⁻¹. The vertical black lines on the spectra indicate the wavelength position at which the image is shown. We have adopted the observer point of view for Doppler shifts in which a negative v_LOS corresponds to a blueshift in the spectral line. The larger yellow squares correspond to the regions that are zoomed into in Fig. 5. Vertical slices along the white markers in the synthetic μ = 1 images are shown in Figs. 1 and 3.