The VMC survey - XLIV: mapping metallicity trends in the large magellanic cloud using near-infrared passbands

Samyaday Choudhury*, Richard de Grijs, Kenji Bekki, Maria-Rosa L. Cioni, Valentin D. Ivanov, Jacco Th van Loon, Amy E. Miller, Florian Niederhofer, Joana M. Oliveira, Vincenzo Ripepi, Ning-Chen Sun, Smitha Subramanian

*Corresponding author for this work

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Abstract

We have derived high-spatial-resolution metallicity maps covering ∼105 deg2 across the Large Magellanic Cloud (LMC) using near-infrared passbands from the VISTA Survey of the Magellanic Clouds. We attempt to understand the metallicity distribution and gradients of the LMC up to a radius of ∼6 kpc. 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 mean LMC metallicity is [Fe/H] = -0.42 dex (σ[Fe/H] = 0.04 dex). We find the bar to be mildly metal-rich compared with the outer disc, showing evidence of a shallow gradient in metallicity (-0.008 +/- 0.001 dex kpc-1) from the galaxy's centre to a radius of 6 kpc. Our results suggest that the LMC's stellar bar is chemically similar to the bars found in large spiral galaxies. The LMC's radial metallicity gradient is asymmetric. It is metal-poor and flatter towards the southwest, in the direction of the Bridge. This hints at mixing and/or distortion of the spatial metallicity distribution, presumably caused by tidal interactions between the Magellanic Clouds.

Original languageEnglish
Pages (from-to)4752-4763
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume507
Issue number4
DOIs
Publication statusPublished - Nov 2021

Bibliographical note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, Volume 507, Issue 4, November 2021, Pages 4752–4763, https://doi.org/10.1093/mnras/stab2446. Copyright 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Keywords

  • stars: abundances
  • Hertzsprung-Russell and colour-magnitude diagrams
  • galaxies: abundanes
  • Local Group
  • Magellanic Clouds

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