The Kaiser-Rocket effect: three decades and counting

TL;DR

The paper investigates the Kaiser-Rocket effect caused by observer motion in galaxy surveys, analyzing its impact, and discusses mitigation strategies for future cosmological data analysis.

Contribution

It provides an analytical and numerical study of the Kaiser-Rocket effect, assessing its significance and proposing methods for mitigation in cosmological surveys.

Findings

The effect can be >5σ in ideal surveys at z~1.5.

For realistic surveys, the effect is not a major concern.

The effect's origin and mitigation strategies are well understood.

Abstract

The peculiar motion of the observer, if not accurately accounted for, is bound to induce a well-defined clustering signal in the distribution of galaxies. This signal is related to the Kaiser rocket effect. Here we examine the amplitude and form of this effect, both analytically and numerically, and discuss possible implications for the analysis and interpretation of forthcoming cosmological surveys. For an idealistic cosmic variance dominated full-sky survey with a Gaussian selection function peaked at $z\sim 1.5$ it is a $> 5\sigma$ effect and it can in principle bias very significantly the inference of cosmological parameters, especially for primordial non-Gaussianity. For forthcoming surveys, with realistic masks and selection functions, the Kaiser rocket is not a significant concern for cosmological parameter inference. However, it is a systematic effect whose origin, nature and imprint on galaxy maps are well known and thus should be subtracted or mitigated. We present several approaches to do so.