Luminosity bias: from haloes to galaxies

Understand

Large surveys of the local Universe have shown that galaxies with different intrinsic properties, such as colour, luminosity and morphological type display a range of clustering amplitudes.

• Galaxies are therefore not faithful tracers of the underlying matter distribution.
• This modulation of galaxy clustering, called bias, contains information about the physics behind galaxy formation.
• It is also a systematic to be overcome before the large-scale structure of the Universe can be used as a cosmological probe.