Camille Bonvin - December 9, 2016

Measuring galaxy velocities with lensing

The size of galaxies is affected not only by gravitational lensing but also by Doppler
effects. In this talk I will show that by cross-correlating the galaxy convergence
with the number count of galaxies we can isolate the Doppler contribution. This
provides an alternative way to redshift-space distortions for measuring the velocities
of galaxies. I will show that the signal-to-noise of this observable is sufficiently
large to allow a detection in current optical surveys as well as in future radio
surveys like the SKA.