Emission-line diagnostic diagram and stacks of one hundred spectra

Left: Emission-line diagnostic diagram of over 200,000 SDSS galaxies, with line measurements from SDSS DR 12. The color-coded classes (Seyfert, star-forming, LINER, and composite galaxies) divide the sample according to their dominant source of ionizing radiation. Right: Stacks of one hundred spectra per galaxy class, with data from SDSS DR16. The spectra were selected randomly from the rectangular regions marked in the left panel. The new spectral access service makes it possible to retrieve hundreds of spectra in just a few seconds, i.e., an improvement of two orders of magnitude over traditional FITS file access. (Figure courtesy of Ragadeepika Pucha).