The Pristine survey

作者：Akshara Viswanathan, Zhen Yuan, Anke Arentsen, Else Starkenburg, Nicolas F. Martin, Kris Youakim, Rodrigo Ibata, Federico Sestito, Tadafumi Matsuno, Carlos Allende Prieto, Freya Barwell, Manuel Bayer, Amandine Doliva-Dolinsky, Emma Fernández-Alvar, P. M. Galán-de Anta, Kiran Jhass, Nicolas Longeard, José María Arroyo-Polonio, Pol Massana, Martin Montelius, Samuel Rusterucci, Judith Santos-Torres, Guillaume F. Thomas, Sara Vitali, Wenbo Wu, Paige Yarker, Xianhao Ye, David S. Aguado, F. Gran, Julio F. Navarro · 发表于：Astronomy and Astrophysics · 年份：2025 · DOI：10.1051/0004-6361/202450819 · 被引用次数：11 · 研究领域：Stellar, planetary, and galactic studies、Astronomy and Astrophysical Research、Astronomical Observations and Instrumentation

Context. The Pristine- Gaia synthetic catalogue of reliable photometric metallicities makes use of spectrophotometric information from Gaia DR3 XP spectra to calculate metallicity-sensitive CaHK magnitudes, which in turn provides photometric metallicities for ~30 million FGK stars using the Pristine survey model and the survey’s training sample. Aims. We performed the first low- to medium-resolution spectroscopic follow-up of bright (G < 15) and distant (upto 35 kpc) very and extremely metal-poor (V/EMP, [Fe/H] < −2.5) red giant branch stars from this catalogue – to evaluate the quality of the photometric metallicities and study the chemodynamics of these V/EMP stars. Methods. We used Isaac Newton Telescope/Intermediate Dispersion Spectrograph (INT/IDS) observations centred around the calcium triplet region ideal for V/EMP stars for this spectroscopic follow-up. Results. We find that 76% of our stars indeed have [Fe/H] < −2.5 with these inferred spectroscopic metallicities, and only 3% are outliers with [Fe/H] > −2.0. We report a success rate of 77% and 38% in finding stars with [Fe/H] < −2.5 and −3.0, respectively. This is a huge improvement compared to the literature in the selection of V/EMP stars based on photometric metallicities and will allow for 10 000–20 000 homogeneously analysed EMP stars using the WEAVE survey follow-up of Pristine EMP candidates. Using kinematics, we categorised 20%, 46%, and 34% of the stars as being confined to the disc plane, or...