Choudhury, S, de Grijs, R, Rubele, S, Bekki, K, Cioni, M-RL, Ivanov, VD, van Loon, JT ORCID: https://orcid.org/0000-0002-1272-3017, Niederhofer, F, Oliveira, JM ORCID: https://orcid.org/0000-0002-0861-7094 and Ripepi, V (2020) The VMC survey – XXXIX: Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands. Monthly Notices of the Royal Astronomical Society, 497 (3). pp. 3746-3760.

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Abstract

We have derived high spatial resolution metallicity maps covering ∼42 deg2 across the Small Magellanic Cloud (SMC) in an attempt to understand its metallicity distribution and gradients up to a radius of ∼ 4○. Using the near-infrared VISTA Survey of the Magellanic Clouds, our data cover a thrice larger area compared with previous studies. We identify red giant branch (RGB) stars in spatially distinct Y, (Y − Ks) colour–magnitude diagrams. In any of our selected subregions, the RGB slope is used as an indicator of the average metallicity, based on calibration to metallicity using spectroscopic data. The metallicity distribution across the SMC is unimodal and can be fitted by a Gaussian distribution with a peak at [Fe/H] = −0.97 dex (σ[Fe/H] = 0.05 dex). We find evidence of a shallow gradient in metallicity (−0.031 ± 0.005 dex deg−1) from the galactic centre to radii of 2○–2.5○, followed by a flat metallicity trend from ∼ 3.5○ to 4○. We find that the SMCâs metallicity gradient is radially asymmetric. It is flatter towards the East than to the West, hinting at mixing and/or distortion of the spatial metallicity distribution (within the inner 3○), presumably caused by tidal interactions between the Magellanic Clouds.

Item Type: Article
Additional Information: © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) The final version of this article can be found at; https://academic.oup.com/mnras/article/doi/10.1093/mnras/staa2140/5875930
Uncontrolled Keywords: stars: abundances, Hertzsprung-Russell and colour-magnitude diagrams, galaxies: abundanes, Local Group, Magellanic Clouds
Subjects: Q Science > Q Science (General)
Q Science > QB Astronomy
Q Science > QB Astronomy > QB460 Astrophysics
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 06 Aug 2020 12:02
Last Modified: 29 Oct 2020 13:07
URI: https://eprints.keele.ac.uk/id/eprint/8480

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