sSFR
Specific star formation rate (sSFR) is a measure used in galaxy evolution to quantify how quickly a galaxy is forming stars relative to its existing stellar mass. It is defined as sSFR = SFR / M*, where SFR is the star formation rate (in solar masses per year) and M* is the stellar mass (in solar masses). The resulting units are inverse time (typically yr^-1 or Gyr^-1).
Conceptually, sSFR indicates the growth rate of a galaxy’s stellar mass if current star formation continues
Measuring sSFR requires estimating both SFR and M*. SFR is inferred from indicators such as ultraviolet light,
sSFR evolves with cosmic time, generally increasing with redshift for star-forming galaxies. This evolution, along with