Tidal origin of NGC 1427A in the Fornax cluster

Abstract

We present new HI observations from the Australia Telescope Compact Array and deep optical imaging from OmegaCam on the VLT Survey Telescope of NGC 1427A, an arrow-shaped dwarf irregular galaxy located in the Fornax cluster. The data reveal a star-less HI tail that contains ~10% of the atomic gas of NGC 1427A as well as extended stellar emission that shed new light on the recent history of this galaxy. Rather than being the result of ram pressure induced star-formation, as previously suggested in the literature, the disturbed optical appearance of NGC 1427A has tidal origins. The galaxy itself likely consists of two individual objects in an advanced stage of merging. The HI tail may be made of gas expelled to large radii during the same tidal interaction. It is possible that some of this gas is subject to ram pressure, which would be considered a secondary effect and imply a northwest trajectory of NGC 1427A within the Fornax cluster.

8 pages, 4 figures

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• Cold gas accretion in galaxies
• SoFiA: a flexible source finder for 3D spectral line data
• An extremely optically dim tidal feature in the gas-rich interacting galaxy group NGC 871/NGC 876/NGC 877
• The old globular cluster system of the dIrr galaxy NGC1427A in the Fornax cluster
• 2MASS Galaxies in the Fornax Cluster Spectroscopic Survey

Cited by in corpus (12)

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• The Fornax Cluster VLT Spectroscopic Survey III -- Kinematical characterisation of globular clusters across the Fornax galaxy cluster
• The MeerKAT Fornax Survey II. The rapid removal of HI from dwarf galaxies in the Fornax cluster
• Formation of an ultra-diffuse galaxy in the stellar filaments of NGC3314A: caught in act?
• A tale of two tails: insights from simulations into the formation of the peculiar dwarf galaxy NGC 1427A
• Evaluating the feasibility of interpretable machine learning for globular cluster detection
• Identification of ram pressure stripping features in galaxies using citizen science
• HI in and behind the Hubble Frontier Field Clusters: A Deep MeerKAT Pilot Search out to $z\sim 0.5$
• The MeerKAT Fornax Survey VI. The collapse of the galaxy HI Mass Function in Fornax
• The MeerKAT Fornax Survey -- I. Survey description and first evidence of ram pressure in the Fornax galaxy cluster