Possible origins of anomalous Ha I gas around MHONGOOSE galaxy, NGC 5068
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Archivos
Fecha
2024-07
Autores
Healy J.
De Blok W.J.G.
Maccagni F.M.
Amram P.
Chemin L.
Combes F.
Holwerda B.W.
Kamphuis P.
Pisano D.J.
Schinnerer E.
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
EDP Sciences
Nombre de Curso
Licencia CC
CC BY 4.0 Attribution 4.0 International
Licencia CC
Resumen
The existing reservoirs of neutral atomic hydrogen gas (HI) in galaxies are insufficient to have maintained the observed levels of star formation without some kind of replenishment. This refuelling of the H I reservoirs is likely to occur at column densities an order of magnitude lower than previous observational limits (NHI, limit ∼ 1019 cm-2 at a 30″ resolution over a linewidth of 20 km s-1). In this paper, we present recent deep HI observations of NGC 5068, a nearby isolated star-forming galaxy observed by MeerKAT as part of the MHONGOOSE survey. With these new data, we were able to detect low column density HI around NGC 5068 with a 3σ detection limit of NHI = 6.4 × 1017 cm-2 at a 90″ resolution over a 20 km s-1 linewidth. The high sensitivity and resolution of the MeerKAT data reveal a complex morphology of the HI in this galaxy, a regularly rotating inner disk coincident with the main star-forming disk of the galaxy, a warped outer disk of low column density gas (NHI < 9 × 1019 cm-2), in addition to clumps of gas on the north-western side of the galaxy. We employed a simple two disk model that described the inner and outer disks, which enabled us to identify anomalous gas that deviates from the rotation of the main galaxy. The morphology and the kinematics of the anomalous gas suggest a possible extra-galactic origin. We explore a number of possible origin scenarios that may explain the anomalous gas, and conclude that fresh accretion is the most likely scenario.
Notas
Indexación: Scopus.
Palabras clave
Galaxies: evolution, Galaxies: individual: NGC 5068, Galaxies: ISM, Radio lines: ISM
Citación
Astronomy and Astrophysics Open Access Volume 6871 July 2024 Article number A254
DOI
10.1051/0004-6361/202347475