Bulk flow and shear in the local Universe: 2MTF and COSMICFLOWS-3
  The low-order kinematic moments of galaxies, namely bulk flow and shear,
enables us to test whether theoretical models can accurately describe the
evolution of the mass density field in the nearby Universe. We use the
so-called etaMLE maximum likelihood estimator in logdistance space to measure
thesemoments from a combined sample of the 2MASS Tully-Fisher (2MTF) survey and
the COSMICFLOWS-3 (CF3) compilation. Galaxies common between 2MTF and CF3
demonstrate a small zero-point difference of -0.016+-0.002 dex.We test the
etaMLE on 16 mock 2MTF survey catalogues in order to explore how well the
etaMLE recovers the true moments, and the effect of sample anisotropy. On the
scale size of 37 Mpc/h, we find that the bulk flow of the local Universe is 259
+- 15 km/h in the direction is (l,b)=(300+-4, 23+-3) (Galactic coordinates).
The average shear amplitude is 1.7+-0.4 h km/s/Mpc. We use a variable window
function to explore the bulk and shear moments as a function of depth. In all
cases, the measurements are consistent with the predictions of the L cold dark
matter (LCDM) model.
