Multicomponent Gaussian analysis of the VELC Fe XIV 5303 Å spectra during the CME passage. (a) and (b) show spectra along Slit S4 at the preevent reference time (12:40:13 UT) and during the CME passage (13:28:48 UT), respectively. (c) and (d) present at Solar Y = −1^″ and Solar Y = −106^″, respectively, at the locations marked by the yellow line segments in panels (a) and (b). The observed profiles (dark gray) are compared with the preevent reference profiles (green). The double-Gaussian fits (red) consist of a primary core component (yellow) and a Doppler-shifted secondary component (blue). The fitted intensity, Doppler velocity, and FWHM are printed for each component, with subscripts 1 and 2 denoting the primary and secondary components, respectively. The shaded wavelength regions are excluded from the fits. The lower panels show the corresponding postfit residuals.