Bulk flows from galaxy luminosities: application to 2MASS redshift survey and forecast for next-generation datasets

Understand

We present a simple method for measuring cosmological bulk flows from large redshift surveys, based on the apparent dimming or brightening of galaxies due to their peculiar motion.

• It is aimed at estimating bulk flows of cosmological volumes containing large numbers of galaxies.
• Constraints on the bulk flow are obtained by minimizing systematic variations in galaxy luminosities with respect to a reference luminosity function measured from the whole survey.
• This method offers two advantages over more popular bulk flow estimators: it is independent of error-prone distance indicators and of the poorly-known galaxy bias.