Perturbed redshifts from N-body simulations

Understand

In order to keep pace with the increasing data quality of astronomical surveys the observed source redshift has to be modeled beyond the well-known Doppler contribution.

• In this letter I want to examine the gauge issue that is often glossed over when one assigns a perturbed redshift to simulated data generated with a Newtonian N-body code.
• A careful analysis reveals the presence of a correction term that has so far been neglected.
• It is roughly proportional to the observed length scale divided by the Hubble scale and therefore suppressed inside the horizon.