Early observations of the MHONGOOSE galaxies: getting ready for MeerKAT

• Published in: Monthly notices of the Royal Astronomical Society 2019-01, Vol.482 (1), p.1248-1269
• Main Authors: Sorgho, A, Carignan, C, Pisano, D J, Oosterloo, T, de Blok, W J G, Korsaga, M, Pingel, N M, Sardone, Amy, Goedhart, S, Passmoor, S, Dikgale, A, Sirothia, S K
• Format: Article
• Language: English
• Subjects: Sciences of the Universe
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/sty2785

We present early observations of 20 galaxies in the MHONGOOSE survey galaxies using KAT-7, the GBT, and MeerKAT. We present the best calibrators for five of the MHONGOOSE galaxies observed with the KAT-7, and search for signs of gas accretion in the GBT data, down to 3σ column density levels of 2.2× 10^{18} cm^{-2} over a 20 km s-1 line width, but identify none. Using the KAT-7 and MeerKAT data, we have derived rotation curves and mass models for NGC 3621 and NGC 7424, respectively, out to an unprecedented extent. As a precursor to the SKA, the MeerKAT telescope combines both a high spatial resolution and a large field of view, necessary to map the extended neutral hydrogen in local galaxies. The mass models of the two galaxies were constructed for both the Dark Matter (DM) models (the pseudo-isothermal model and the Navarro-Frenk-White model) and MOND. Overall, we find that the DM models provide a better fit than MOND to the galaxies' rotation curves. Furthermore, the pseudo-isothermal model is found to be the most consistent with the observations.