BPT diagram derived from spectral fit results for galaxy companions of PDS 456. The top panel displays the spectra and their best-fit models, while the bottom panel presents the [N II] -BPT diagram, for the galaxy companions of PDS 456. These spectra were extracted from circular regions with a radius of 2 pixels in the datacube, where the nuclear and continuum emission components of PDS 456 have been subtracted. The transparent gray dots show the values from the SDSS survey (credits: Jake Vanderplas & AstroML Developers). The black lines dividing different types of emissions in the BPT diagram are from Kewley et al. (2001).