University of Oulu

K. Lee-Waddell, P. Serra, B. Koribalski, A. Venhola, E. Iodice, B. Catinella, L. Cortese, R. Peletier, A. Popping, O. Keenan, M. Capaccioli; Tidal origin of NGC 1427A in the Fornax cluster, Monthly Notices of the Royal Astronomical Society, Volume 474, Issue 1, 11 February 2018, Pages 1108–1115,

Tidal origin of NGC 1427A in the Fornax cluster

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Author: Lee-Waddell, K.1; Serra, P.1,2; Koribalski, B.1;
Organizations: 1CSIRO Astronomy and Space Sciences, Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia
2INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (CA), Italy
3Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700 AV Groningen, the Netherlands
4Astronomy Research Unit, University of Oulu, FI-90014 Oulu, Finland
5INAF – Astronomical Observatory of Capodimonte, via Moiariello 16, Naples I-80131, Italy
6International Centre for Radio Astronomy Research, The University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia
7ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
8School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
9Dip.di Fisica Ettore Pancini, University of Naples ‘Federico II’, C.U. Monte SantAngelo, Via Cinthia, I-80126 Naples, Italy
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.8 MB)
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Language: English
Published: Oxford University Press, 2018
Publish Date: 2018-03-12


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 per cent 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 implies a north-west trajectory of NGC 1427A within the Fornax cluster.

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Series: Monthly notices of the Royal Astronomical Society
ISSN: 0035-8711
ISSN-E: 1365-8711
ISSN-L: 0035-8711
Volume: 474
Pages: 1108 - 1115
DOI: 10.1093/mnras/stx2808
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
114 Physical sciences
Funding: The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a national facility managed by CSIRO. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 679627; project name FORNAX). BC is the recipient of an Australian Research Council Future Fellowship (FT120100660).
Copyright information: © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Published in this repository with the kind permission of the publisher.