2025MNRAS.544..457P

We present the gradients of the Large Magellanic Cloud (LMC) for 25 elemental abundances and abundance ratios with their respective temporal evolution as well as age-[X/Fe] trends using 6130 LMC field red giant branch (RGB) stars observed by SDSS-IV / APOGEE-2S. APOGEE is a high resolution (R $\sim$ 22 500) H-band spectroscopic survey that gathered data on the LMC with broad radial and azimuthal coverage out to $\sim$10$^\circ$. The calculated overall metallicity ([Fe/H]) gradient of the LMC with no age binning is -0.0296 $\pm$ 0.0017 dex kpc^–1. We also find that many of the gradients ($\nabla _R$[X/H]) show a U-shaped trend as functions of age. This trend is marked by a flattening of the gradient but then a general steepening at more recent times. The extremum point at which all these gradients (with the U-shaped trend) begin to steepen is $\gtrsim$2 Gyr ago. In addition, some of the age-[X/Fe] trends show an increase starting a few Gyr before the extremum point in the gradient evolutions. A subset of the age-[X/Fe] trends also show maxima concurrent with the gradients' extremum points, further pinpointing a major event in the history of the LMC $\sim$2 Gyr ago. This time frame aligns with a known Magellanic Clouds interaction, likely driving the gradient and age-[X/Fe] trends seen. In the future, ongoing or recent mergers can be studied potentially using similar patterns like the ones found here.