Speaker
Description
In this study, we examine the novel effects of peculiar velocities on color selection in galaxy surveys, with a focus on their implications for the analysis of large-scale structure. Our work quantifies the interplay between the peculiar velocities of Emission Line Galaxies (ELGs) and the color filters employed in the DESI survey. We show that these velocities can shift spectral emission features into or out of filter bands, modifying galaxy colors and thereby influencing selection criteria. This phenomenon mimics the effect of evolution bias but can exceed it by as much as an order of magnitude. We illustrate that ELGs’ susceptibility to minor spectral shifts induced by peculiar velocities stems from their notably intense emission lines. Our results underscore that peculiar velocities markedly affect the ELG-LRG (Luminous Red Galaxy) multi-tracer dipole power spectrum and also impart smaller, yet significant, changes to the ELG single tracer statistics. This work highlights the essential need for careful consideration of spectral-dependent biases caused by peculiar velocities during the selection phase of galaxy surveys, to ensure an unbiased analysis of cosmological surveys.
