HI galaxy signatures in the SARAO MeerKAT galactic plane survey - III. Unveiling the obscured part of the Vela Supercluster

We conducted a search for emission of the gas-rich galaxies in the Vela region (260° ≤ ℓ ≤ 290°, -2° ≤ b ≤ 1°) to explore the Vela Supercluster (VSCL) at V_hel ∼18 000, largely obscured by Galactic dust. Within the mostly Radio Frequency Interference-free band (250 < V_hel < 25 000) of MeerKAT, the analysis focuses on 157 hexagonally distributed pointings extracted from the South African Radio Astronomy Observatory MeerKAT Galactic Plane Survey located in the Vela region (Vela-SMGPS). These were combined into 10 contiguous mosaics, covering an ∼90 square degrees area. Among the 843 detected sources, 39 were previously discovered in the H i Parkes Zone of Avoidance survey (V_hel < 12 000; rms ∼6). With the improved rms level of the Vela-SMGPS, i.e. 0.29-0.56, our study unveils nearly 12 times more detections (471 candidates) in that same velocity range. We furthermore could identify 187 galaxy candidates with an mass limit reaching in the VSCL velocity range V_hel ∼19 500 ± 3500. We find indications of two wall-like overdensities that confirm the original suspicion that these walls intersect at low latitudes around longitudes of ℓ ∼272°-278°. We also find a strong signature most likely associated with the Hydra/Antlia extension and evidence of a previously unknown narrow filament at V_hel ∼12 000. This paper demonstrates the efficiency of systematic surveys with the Square Kilometre Array (SKA) precursor MeerKAT, even in the most obscured part of the Zone of Avoidance.