1. H i galaxy signatures in the SARAO MeerKAT galactic plane survey − III. Unveiling the obscured part of the Vela Supercluster.
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Rajohnson, Sambatriniaina H A, Kraan-Korteweg, Renée C, Chen, Hao, Frank, Bradley S, Steyn, Nadia, Kurapati, Sushma, Pisano, D J, Staveley-Smith, Lister, Serra, Paolo, Goedhart, Sharmila, and Camilo, Fernando
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MEERKAT ,GALAXIES ,RADIO frequency ,ASTRONOMICAL observatories ,LARGE scale structure (Astronomy) ,RADIO astronomy - Abstract
We conducted a search for |$\textrm {H}\, \scriptstyle \mathrm{I}$| 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 |$\rm km\, s^{-1}$| , largely obscured by Galactic dust. Within the mostly Radio Frequency Interference-free band (250 < Vhel < 25 000 |$\rm km\, s^{-1}$|) 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 |$\textrm {H}\, \scriptstyle \mathrm{I}$| detected sources, 39 were previously discovered in the H i Parkes Zone of Avoidance survey (Vhel < 12 000 |$\rm km\, s^{-1}$| ; rms ∼ 6 |$\rm mJy\, beam^{-1}$|). With the improved rms level of the Vela−SMGPS, i.e. 0.29–0.56 |$\rm mJy\, beam^{-1}$| , our study unveils nearly 12 times more detections (471 candidates) in that same velocity range. We furthermore could identify 187 galaxy candidates with an |$\textrm {H}\, \scriptstyle \mathrm{I}$| mass limit reaching |$\log (M_{\rm HI}/\rm {\rm M}_{\odot }) = 9.44$| in the VSCL velocity range Vhel ∼ 19 500 ± 3500 |$\rm km\, s^{-1}$|. 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 Vhel ∼ 12 000 |$\rm km\, s^{-1}$|. This paper demonstrates the efficiency of systematic |$\textrm {H}\, \scriptstyle \mathrm{I}$| surveys with the Square Kilometre Array (SKA) precursor MeerKAT, even in the most obscured part of the Zone of Avoidance. [ABSTRACT FROM AUTHOR]- Published
- 2024
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