H I galaxy signatures in the SARAO MeerKAT Galactic Plane Survey - I. Probing the richness of the great attractor wall across the inner zone of avoidance
Abstract
This paper presents the first H I results extracted from the South African Radio Astronomy Observatory (SARAO) MeerKAT Galactic Plane Survey (SMGPS) - a narrow strip (Δb ~ 3°) along the southern Milky Way. The primary goal consisted in tracing the great attractor (GA) wall across the innermost zone of avoidance. We reduced a segment spanning the longitude range 302° ≤ ℓ ≤ 332° for the redshift range z ≤ 0.08. The superb SMGPS sensitivity (rms = 0.3-0.5 mJy beam-1 per 44 km s-1 channel) and angular resolution (~31″ × 26″) lead to a detection limit of log(MH I/M⊙) ≥ 8.5 at the GA distance ($\mbox{$V_{\rm {hel}}$}\, \sim 3500{\!-\!}6500$ km s-1). A total of 477 galaxy candidates were identified over the full redshift range. A comparison of the few H I detections with counterparts in the literature (mostly HIZOA) found the H I fluxes and other H I parameters to be highly consistent. The continuation of the GA wall is confirmed through a prominent overdensity of N = 214 detections in the GA distance range. At higher latitudes, the wall moves to higher redshifts, supportive of a possible link with the Ophiuchus cluster located behind the Galactic Bulge. This deep interferometric H I survey demonstrates the power of the SMGPS in improving our insight of large-scale structures at these extremely low latitudes, despite the high obscuration and continuum background.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2024
- DOI:
- 10.1093/mnrasl/slad196
- arXiv:
- arXiv:2312.03545
- Bibcode:
- 2024MNRAS.529L..88S
- Keywords:
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- surveys;
- galaxies: distances and redshifts;
- large-scale structure of Universe;
- radio lines: galaxies;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 5 pages, 7 figures, 2 appendices of 12 pages. Journal reference: MNRAS Letters, accepted