The AMBRE Project: Spectrum normalisation influence on Mg abundances in the metal-rich Galactic disc

Abstract

The abundance of α-elements provides an important fossil signature in Galactic archaeology to trace the chemical evolution of the different disc populations. High-precision chemical abundances are crucial to improving our understanding of the chemodynamical properties present in the Galaxy. However, deriving precise abundance estimations in the metal-rich disc ([M/H] > 0 dex) is still challenging. The aim of this paper is to analyse different error sources affecting magnesium abundance estimations from optical spectra of metal-rich stars. We derived Mg abundances for 87522 high-resolution spectra of 2210 solar neighbourhood stars from the AMBRE Project. For this purpose, the GAUGUIN automated abundance estimation procedure was employed. The normalisation procedure has a strong impact on the derived abundances, with a clear dependence on the stellar type and the line intensity. For non-saturated lines, the optimal wavelength domain for the local continuum placement should be evaluated using a goodness-of-fit criterion, allowing mask-size dependence with the spectral type. Moreover, for strong saturated lines, applying a narrow normalisation window reduces the parameter-dependent biases of the abundance estimate, increasing the line-to-line abundance precision. In addition, working at large spectral resolutions always leads to better results than at lower ones. The resulting improvement in the abundance precision makes it possible to observe both a clear thin-thick disc chemical distinction and a decreasing trend in the magnesium abundance even at supersolar metallicities. In the era of precise kinematical and dynamical data, optimising the normalisation procedures implemented for large spectroscopic stellar surveys would provide a significant improvement to our understanding of the chemodynamical patterns of Galactic populations.

Accepted for publication in A&A

References in corpus (16)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Radial Velocity Experiment (RAVE): first data release
• The GALAH Survey: Scientific Motivation
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• The Gaia-ESO Survey: the Galactic Thick to Thin Disc transition
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• Automated derivation of stellar atmospheric parameters and chemical abundances: the MATISSE algorithm
• Atomic and Molecular Data for Optical Stellar Spectroscopy
• The Gaia-ESO Survey: the chemical structure of the Galactic discs from the first internal data release
• The AMBRE Project: chemical evolution models for the Milky Way thick and thin discs
• The AMBRE project: The thick thin disk and thin thick disk of the Milky Way
• The Rich Are Different: Evidence from the RAVE Survey for Stellar Radial Migration
• Open clusters in APOGEE and GALAH: Combining Gaia and ground-based spectroscopic surveys
• The AMBRE Project: Constraining the lithium evolution in the Milky Way
• Revisiting long-standing puzzles of the Milky Way: the Sun and its vicinity as typical outer disk chemical evolution
• The AMBRE Project: Parameterisation of FGK-type stars from the ESO:HARPS archived spectra

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