Bibliographic Details
| Title: |
The Pristine Survey -- XXVII. Journey to the Galactic outskirts -- Mapping the outer halo red giant stars down to the very metal-poor end |
| Authors: |
Viswanathan, Akshara, Byström, Amanda, Starkenburg, Else, Foppen, Anne, Straat, Jill, Montelius, Martin, Sestito, Federico, Venn, Kim A., Navarrete, Camila, Matsuno, Tadafumi, Martin, Nicolas F., Thomas, Guillaume F., Ardern-Arentsen, Anke, Battaglia, Giuseppina, Fouesneau, Morgan, Navarro, Julio, Vitali, Sara |
| Publication Year: |
2024 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
Context: In the context of Galactic archaeology, the outer halo remains relatively unexplored with respect to its metallicity distribution, merger debris, and the abundance of known very/extremely metal-poor ([Fe/H]<-2.5) stars. Aim: We utilize the Pristine survey's publicly available, Pristine data release 1 (PDR1) and Pristine-Gaia synthetic (PGS) catalogues of photometric metallicities, to select Red Giant Branch (RGB) stars in the outer halo. Methods: The RGB selection pipeline selects giants based on the absence of a well-measured parallax in the brightness range where dwarfs have reasonable parallax estimate from Gaia DR3 data. The photometric distances are calculated using a BaSTI-isochrone fitting code and the photometric metallicities. Results: Photometric distances derived from PDR1- and PGS-giants show typical uncertainties of 12% and a scatter of up to 20% and 40% respectively, when validated against inverted-parallax and Starhorse-code distances. The PDR1-giants catalogue provides a low-to-no bias view of the metallicity structure versus distance compared to the PGS-giants catalogue (with a distance-metallicity selection bias), while the PGS-giants catalogue provides an all-sky view of the outer halo, especially in the VMP end. The PDR1-giants catalogue is used to study the metallicity distribution function of the halo out to ~100 kpc, using Gaussian Mixture Model decomposition. Additionally, we use the PDR1-giants with radial velocities from spectroscopic surveys to map the metallicity view of the integrals-of-motion space where accreted dwarf galaxy debris conserve their orbital parameters for a long time. Using the PGS-giants catalogue, we associate 41 stars tentatively to the stellar counterpart of the Magellanic stream in the VMP end, out to 70 kpc. Conclusions: We publish two RGB catalogues between -4.0<[Fe/H]<+0.1 with reliable photometric distances and metallicities.
Comment: Submitted to A&A, 25 pages (19 Figures) + 4 pages (6 Figures) in Appendix. Comments are very welcome, enjoy reading! The catalogues will be published upon acceptance |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2408.17250 |
| Accession Number: |
edsarx.2408.17250 |
| Database: |
arXiv |
