Measuring our velocity from fluctuations in number counts
  Our velocity relative to the cosmic microwave background (CMB) generates a
dipole from the CMB monopole, which was accurately measured by COBE. The
relative velocity also modulates and aberrates the CMB fluctuations, generating
a small signature of statistical isotropy violation in the covariance matrix.
This signature was first measured by Planck 2013. Galaxy surveys are similarly
affected by a Doppler boost. The dipole generated from the number count
monopole has been extensively discussed, and measured (at very low accuracy) in
the NVSS and TGSS radio continuum surveys. For the first time, we present an
analysis of the Doppler imprint on the number count fluctuations, using the
bipolar spherical harmonic formalism to quantify these effects. Next-generation
wide-area surveys with a high redshift range are needed to detect the small
Doppler signature in number count fluctuations. We show that radio continuum
surveys with the SKA should enable a detection at $\gtrsim 3 \sigma$ in Phase
2, with marginal detection possible in Phase 1.
