Description |
The study of peculiar velocity in the low redshift Universe plays an important role in observational cosmology in two main ways: i) It introduces correlated errors in the measurement of the redshifts, potentially making up a non-negligible fraction of the systematic error budget in the measurement of the expansion history, ii) Peculiar velocities are the only probe of growth of structure in the very low-redshift Universe. In this talk, I will present some recent results on both of these aspects. First, I will present some results from our investigation into the role of peculiar velocity corrections in the measurement of $H_0$. I will show that assumptions on the line-of-sight peculiar velocity can lead to significant differences in the measured value of $H_0$. Then, I will present results of constraints on cosmological parameters from velocity-velocity comparison. The constraints on $f\sigma_8$ from peculiar velocities are competitive and complementary to probes of structure growth at high redshifts.
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