Detalles de publicación
PP 025019
The GECKOS Survey: Identifying kinematic sub-structures in edge-on galaxies
1 European Southern Observatory,
2 ARC Centre of Excellence for All Sky Astrophysics in Three Di-
mensions (ASTRO-3D)
3 School of Physics, University of New South Wales,
4 Centre for Extragalactic Astronomy, Durham University,
5 National Research Council of Canada,
6 Centre for Astrophysics and Supercomputing, Swinburne University
of Technology,
7 Astrophysics Research Institute, Liverpool John Moores University,
8 Sub-department of Astrophysics, Department of Physics, University
of Oxford,
9 Max-Planck-Institut für Extraterrestrische Physik,
10 International Centre for Radio Astronomy Research (ICRAR), The
University of Western Australia,
11 Research School of Astronomy and Astrophysics, Australian Na-
tional University,
12 Sydney Institute for Astronomy, School of Physics, The Uni-
versity of Sydney,
13 Observatoire de Paris,
14 Collège de France,
15 Cardiff Hub for Astrophysics Research & Technology, School of
Physics & Astronomy, Cardiff University,
16 Instituto de Astrofísica de Canarias,
17 Departamento de Astrofísica, Universidad de La Laguna,
18 Institute for Computational Cosmology, Department of Physics,
Durham University,
19 Homer L. Dodge Department of Physics & Astronomy, University
of Oklahoma,
20 Research Centre for Astronomy, Macquarie University, 21 European Southern Observatory, Chile,
22 Universidade Cidade de São Paulo/Universidade Cruzeiro do Sul,
23 Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-
Universität München,
24 Department of Astrophysics, University of Vienna,
25 Department of Physics and Astronomy, University of Utah
The vertical evolution of galactic discs is governed by the sub-structures within them. We examine the diversity of kinematic sub-structure present in the first 12 galaxies observed from the GECKOS survey, a VLT/MUSE large programme providing a systematic study of 35 edge-on, Milky Way-mass disc galaxies. Employing the nGIST analysis pipeline, we derive the mean line-of-sight stellar velocity (V⋆), velocity dispersion (σ⋆), skew (h3), and kurtosis (h4) for the sample, and examine 2D maps and 1D line profiles. Visually, the majority of this sample (8/12) are found to possess boxy-peanut bulges and host the corresponding kinematic structure predicted for stellar bars viewed in projection. Four galaxies exhibit strong evidence for the presence of nuclear discs, including central h3-V⋆ anti-correlations, `croissant'-shaped central depressions in σ⋆ maps, strong gradients in h3, and positive h4 plateaus over the expected nuclear disc extent. The strength of the h3 feature corresponds to the size of the nuclear disc, measured from the h3 turnover radius. We can explain the features within the kinematic maps of all sample galaxies via disc structure(s) alone. We do not find any need to invoke the existence of dispersion-dominated bulges. Obtaining the specialised data products for this paper and the broader GECKOS survey required significant development of existing integral field spectroscopic (IFS) analysis tools. Therefore, we also present the nGIST pipeline: a modern, sophisticated, and easy-to-use pipeline for the analysis of galaxy IFS data. We conclude that the variety of kinematic sub-structures seen in GECKOS galaxies requires a contemporary view of galaxy morphology, expanding on the traditional view of galaxy structure, and uniting the kinematic complexity observed in the Milky Way with the extragalactic.