Adi Nusser, Enzo Branchini, Marc Davis
Using redshifts as proxy for galaxy distances, estimates of the 2D transverse
peculiar velocities of distant galaxies ($cz\ltsim 2\times 10^4 \kms$) can be
obtained from Gaia's measurements of proper motions. Owing to the large number
of galaxies expected to be observed by Gaia, these transverse velocities are
likely to supersede traditional probes of the large scale velocity field based
on current and future distance indicator measurements. This Gaia probe of large
scale motions is completely independent of any intrinsic relations between
galaxy properties, hence it is essentially free of selection biases. It is also
free from {homogeneous and} inhomogeneous Malmquist biases that typically
plague distance indicator catalogs. Further, it provides additional information
to traditional probes which yield line-of-sight peculiar velocities.
View original:
http://arxiv.org/abs/1202.4138
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