Baldwin effect (astronomy)

In the context of astronomy, the "Baldwin effect" refers to a correlation observed in the properties of quasars, particularly the relationship between the luminosity of a quasar and the equivalent width of certain emission lines, such as the magnesium II line. This effect suggests that more luminous quasars tend to have weaker emission lines, which can be interpreted as a result of different physical processes occurring in these high-energy environments. The phenomenon is named after the astronomer James A.