Hidden Vela supercluster revealed by the first hybrid redshift and peculiar velocity reconstruction

A large fraction of the extragalactic sky is obscured by foreground dust and stars along the plane of the Milky Way, leaving a major gap (≈20%) in whole-sky maps of large-scale structures – an incompleteness that is even more severe for peculiar velocity samples. This has long limited an unambiguous interpretation of observed cosmic flows and their connection to the underlying mass-density field. We present a new hybrid reconstruction methodology that combines 65 518 galaxy peculiar velocity distances from the CF4++ catalogue with 8283 new galaxy redshifts observed near the southern Galactic plane (| b |≤10°) zone of avoidance (ZOA). A major advance is the inclusion of 2176 high-sensitivity, interferometric H I redshifts obtained with the SARAO MeerKAT telescope, which, for the first times provides coverage of the innermost 3°-wide strip of the southern ZOA and to an unprecedented depth. This hybrid redshift–peculiar velocity approach yields a substantially revised picture of the inferred over-density field in and around the zone of avoidance. In particular, the Vela supercluster emerges as a dominant mass concentration, approaching that of the Shapley concentration and exceeding the mass associated with Laniakea and the Great Attractor region. At a distance of 189 h −1 Mpc, a total mass of 30.6 × 10 16 M ⊙ , a characteristic radius of 74 h −1 Mpc, and a double core morphology, Vela dominates the mass budget and gravitational influence of the southern ZOA. These results provide the most complete and dynamically consistent picture to date of the southern ZOA and demonstrate the transformative potential of hybrid reconstruction techniques tailored for the next generation of large-scale surveys.