BzK galaxy

In astrophysics, a BzK galaxy is a galaxy that has been selected as star-forming or passive based on its photometry in the B, z, and K photometric bands.

The selection criteria, as originally defined,^[1] are as follows:

• Star-forming BzK (sBzK) galaxies satisfy: ${\displaystyle BzK\equiv (z-K)_{AB}-(B-z)_{AB}\geq -0.2}$
• Passive BzK (pBzK) galaxies satisfy: ${\displaystyle BzK<-0.2}$ and ${\displaystyle (z-K)_{AB}>2.5}$