Broad emission lines

Broad emission lines are features observed in the spectra of some active galaxies and quasars. They result from high-speed gas clouds near a supermassive black hole, moving at thousands of kilometers per second. As these clouds are energized by the black hole's activity, they emit light at specific wavelengths, creating bright lines. Because the gas moves so fast, these lines are spread out or "broadened" compared to narrower lines from slower-moving gas. This broadening helps scientists understand the dynamics and environment close to the black hole, providing insights into the extreme conditions present in these energetic regions.