Uncertainties in the Hubble constant from peculiar velocities

Recent measurements of the Hubble constant using type Ia supernovae explicitly correct for their estimated peculiar velocities using the 2M++ reconstruction of the local density field. The amount of uncertainty from this reconstruction procedure has thus far been unquantified. To rectify this, we use mock universe realisations of the 2M++ catalogue and generate predicted peculiar velocities using the same method as the predictions that are used to correct for the Pantheon+ catalogue. We find that the method yields uncertainties of ∼ 0.3 km s -1 Mpc -1 and hence subdominant to the total uncertainty in H 0 .