The GALAH survey : stellar parameters and abundances for 800 000 Gaia RVS spectra using GALAH DR4 and The Cannon

Das, Pradosh Barun (author), Zucker, Daniel B. (author), De Silva, Gayandhi M. (author), Borsato, Nicholas W. (author), Mura-Guzman, Aldo (author), Buder, Sven (author), Kos, Janez (author)

Analysing stellar parameters and abundances from nearly one million Gaia Data Release 3 (DR3) Radial Velocity Spectrometer (RVS) spectra poses challenges due to the limited spectral coverage (restricted to the infrared Ca II triplet) and variable signal-to-noise ratios of the data. To address this, we use The Cannon, a data-driven method, to transfer stellar parameters and abundances from the GALAH (GALactic Archaeology with HERMES) DR4 (R ∼ 28 000) catalogue to the lower resolution Gaia DR3 RVS spectra (R ∼ 11 500). Our model, trained on 14 484 common targets, predicts parameters such as Teff , log g, and [Fe/H], along with several other elements across approximately 800 000 Gaia RVS spectra. We utilize stars from open and globular clusters present in the Gaia RVS catalogue to validate our predicted mean [Fe/H] with high precision (∼ 0.02−0.10 dex). Additionally, we recover the bimodal distribution of [Ti/Fe] versus [Fe/H], reflecting the high and low α-components of Milky Way disc stars, demonstrating The Cannon’s capability for accurate stellar abundance determination from medium-resolution Gaia RVS spectra. The methodologies and resultant catalogue presented in this work highlight the remarkable potential of the RVS data set, which by the end of the Gaia mission will comprise spectra of over 200 million stars.

• Language: English
• Keywords: astrophysics of galaxies, spectroscopic survey
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication date: 01.04.2025
• Year: 2025
• Number of pages: 16 str.
• Numbering: Vol. 538, issue 2
• PID: 20.500.12556/RUL-168911
• UDC: 524.8
• ISSN on article: 1365-2966
• DOI: 10.1093/mnras/staf169
• COBISS.SI-ID: 234816003
• Publication date in RUL: 06.05.2025

Record is a part of a journal

• Title: Monthly notices of the Royal Astronomical Society
• Shortened title: Mon. not. R. Astron. Soc.
• Publisher: Blackwell Science
• ISSN: 1365-2966
• COBISS.SI-ID: 1870180