Magnification and evolution biases in large-scale structure surveys

Understand

Measurements of galaxy clustering in upcoming surveys such as those planned for the Euclid and Roman satellites, and the SKA Observatory, will be sensitive to distortions from lensing magnification and Doppler effects, beyond the standard redshift-space distortions.

• The amplitude of these contributions depends sensitively on magnification bias and evolution bias in the galaxy number density.
• Magnification bias quantifies the change in the observed number of galaxies gained or lost by lensing magnification, while evolution bias quantifies the physical change in the galaxy number density relative to the conserved case.
• These biases are given by derivatives of the number density, and consequently are very sensitive to the form of the luminosity function.