| Title: |
The Pristine survey -- XXVI. The very metal-poor Galaxy: Chemodynamics through the follow-up of the Pristine-Gaia synthetic catalogue |
| Authors: |
Viswanathan, Akshara, Yuan, Zhen, Ardern-Arentsen, Anke, Starkenburg, Else, Martin, Nicolas F., Youakim, Kris, Ibata, Rodrigo A., Sestito, Federico, Matsuno, Tadafumi, Prieto, Carlos Allende, Barwell, Freya, Bayer, Manuel, Doliva-Dolinsky, Amandine, Fernandez-Alvar, Emma, Anta, Pablo M. Galan-de, Jhass, Kiran, Longeard, Nicolas, Arroyo-Polonio, Jose Maria, Massana, Pol, Montelius, Martin, Rusterucci, Samuel, Santos, Judith, Thomas, Guillaume F., Vitali, Sara, Wu, Wenbo, Yarker, Paige, Ye, Xianhao, Aguado, David S., Gran, Felipe, Navarro, Julio |
| Source: |
A&A 695, A112 (2025) |
| Publication Year: |
2024 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
The Pristine-\textit{Gaia} synthetic catalogue provides reliable photometric metallicities for $\sim$30 million FGK stars using the Pristine survey model and Gaia XP spectra. We perform the first low-to-medium-resolution spectroscopic follow-up of bright (G<15) and distant (up to 35 kpc) very and extremely metal-poor (V/EMP, [Fe/H]<-2.5) red giant branch stars from this. We use Isaac Newton Telescope/Intermediate Dispersion Spectrograph (INT/IDS) observations centred around the calcium triplet region ideal for V/EMP stars. We find that 76\% of our stars indeed have [Fe/H]<-2.5 with these inferred spectroscopic metallicities and only 3\% are outliers with [Fe/H] > -2.0. We report a success rate of 77\% and 38\% in finding stars with [Fe/H]<-2.5 and -3.0 respectively. This will allow for 10,000-20,000 homogeneously analysed EMP stars using the WEAVE survey follow-up of Pristine EMP candidates. We associate 20\%, 46\%, and 34\% of the stars to be confined to the disc plane, or to have inner and outer halo orbits, respectively. We also associate these V/EMP stars to known accretion events such as Gaia-Enceladus-Sausage (GES), LMS-1/Wukong, Thamnos, Helmi streams, Sagittarius, Sequoia, etc. For the stars that orbit close to the disc plane, we find that the prograde region with low vertical action is overdense with a significance of 4$\sigma$ as compared to its retrograde counterpart. We also find three new (brightest) members of the most metal-poor stellar stream, C-19, one of which is 50$^\circ$ away from the main body of the stream. Our measured mean metallicity, velocity dispersion, and stream width are consistent with the literature, but our results favour a higher distance ($\sim$21.5 kpc) for the stream. We publish a catalogue (and 1D spectra) of 215 V/EMP stars from this spectroscopic follow-up and showcase the power of chemokinematic analysis of V/EMP end.
Comment: Submitted to A&A. 17 pages (9 figures) + 3 pages (3 figures) in Appendix. Comments are very welcome! The catalogue and 1D spectra will be made available public after acceptance and before upon reasonable request to the first author |
| Document Type: |
Working Paper |
| DOI: |
10.1051/0004-6361/202450819 |
| Access URL: |
http://arxiv.org/abs/2405.13124 |
| Accession Number: |
edsarx.2405.13124 |
| Database: |
arXiv |
