Rest-frame optical spectrum of SDSS J1532 (top left panel) and best-fitting results of SDSS J1532 with rest-frame spectrum from 3850 Å to 4450 Å (top right panel), from 4750 Å to 5050 Å (bottom left panel) and from 6400 Å to 6800 Å (bottom right panel). In the top subpanels the solid dark green lines show the line spectra; the dashed blue and red lines represent the blueshifted and redshifted components of the narrow Hα, Hβ, Hγ, Hδ, He I, [Ne III], [O III], [N II], and [S II] doublets; the solid blue lines represent the extended components of the [O III] emission lines; the solid green lines represent the broad Hα, Hβ, and Hγ emission lines with the corresponding parameters of the central wavelength (Å), line width σ (Å), and line flux (10⁻¹⁷ erg/s/cm²) listed in the first two lines of the panels; the dashed cyan lines show the continuum emissions $\alpha \times {(\frac{\lambda }{5100\mathrm{\AA }})}^{\beta }$ with parameters listed in the third line. In the bottom subpanels, the solid blue lines represent the residuals computed by subtracting the best-fitting results from the line spectra and then dividing by the uncertainties of the SDSS spectra; the solid and dashed green lines show 0 and ±1, respectively.