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, are as follows:
Star-forming BzK (sBzK) galaxies satisfy: B z K ≡ ( z − K ) A B − ( B − z ) A B ≥ − 0.2 {\displaystyle BzK\equiv (z-K)_{AB}-(B-z)_{AB}\geq -0.2}
Passive BzK (pBzK) galaxies satisfy: B z K < − 0.2 {\displaystyle BzK<-0.2} and ( z − K ) A B > 2.5 {\displaystyle (z-K)_{AB}>2.5}
See also Lyman-break galaxy – Star-forming galaxies at high redshift
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