In astrophysics, a BzK galaxy is a galaxy that has been selected as star-forming or passive based on its

photometry Photometry can refer to: * Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision * Photometry (astronomy), the measurement of the flux or intensity of an astronomical object's electro ...

in the B, z, and K photometric bands. The selection criteria, as originally defined, are as follows: * Star-forming BzK (sBzK) galaxies satisfy:

BzK \equiv (z-K)_ - (B-z)_ \geq -0.2

* Passive BzK (pBzK) galaxies satisfy:

BzK < -0.2

and

(z-K)_ > 2.5

References

Galaxies {{galaxy-stub

See also

References