Hostname: page-component-7dd5485656-wlg5v Total loading time: 0 Render date: 2025-10-30T10:18:48.412Z Has data issue: false hasContentIssue false
  • English
  • Français

Dynamical properties of ancient stars in the inner Milky Way with PIGS

Published online by Cambridge University Press:  30 October 2025

A. Arentsen Open the ORCID record for A. Arentsen [Opens in a new window] ,
G. Monari ,
A. Queiroz ,
E. Starkenburg ,
N. F. Martin  and
C. Chiappini
A. Arentsen*
Affiliation:
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
G. Monari
Affiliation:
Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, F-67000 Strasbourg, France
A. Queiroz
Affiliation:
Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany
E. Starkenburg
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV, Groningen, the Netherlands
N. F. Martin
Affiliation:
Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, F-67000 Strasbourg, France Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
C. Chiappini
Affiliation:
Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany
*
email: anke.arentsen@ast.cam.ac.uk
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We present recent results from the Pristine Inner Galaxy Survey (PIGS), which used metallicity-sensitive narrow-band CaHK photometry to identify and follow up spectroscopically thousands of ancient metal-poor candidates in the bulge. For the spectroscopic PIGS sample, we derive distances with StarHorse and compute orbital properties in a realistic potential including a bar. We find that a significant fraction of metal-poor stars is confined to the inner Galaxy (apocentre < 4 kpc), with an estimated confined fraction of 80%/50% at [Fe/H] = − 1.0/ − 2.0. We also find that the very metal-poor population has a net prograde rotation, with a υϕ ∼ 40 kms−1. It is still under discussion what the origin is of the population of very metal-poor inner Galaxy stars – it is likely a combination of in-situ and accreted stars. In future, spectroscopic observations from 4MOST will be crucial to complete our picture.

Keywords

Galaxy: bulgeGalaxy: haloGalaxy: kinematics and dynamicsstars: Population II

Information

Type
Contributed Paper
Information
Proceedings of the International Astronomical Union , Volume 19 , Symposium S379: Dynamical Masses of Local Group Galaxies , December 2023 , pp. 59 - 64
Check for updates
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of International Astronomical Union

References

Arentsen, A., et al., 2020a, MNRAS, 491, L11 CrossRefGoogle Scholar
Arentsen, A., et al., 2020b, MNRAS, 496, 4964 CrossRefGoogle Scholar
Arentsen, A., et al., 2021, MNRAS, 505, 1239 CrossRefGoogle Scholar
Belokurov, V., Kravtsov, A., 2022, MNRAS, 514, 689 CrossRefGoogle Scholar
Bensby, T., et al., 2019, The Messenger, 175, 35 Google Scholar
Casey, A. R., Schlaufman, K. C., 2015, ApJ, 809, 110 CrossRefGoogle Scholar
Chambers, K. C., et al., 2016, arXiv e-prints, p. arXiv:1612.05560 Google Scholar
Chiappini, C., et al., 2019, The Messenger, 175, 30 Google Scholar
Dillamore, A. M., Belokurov, V., Evans, N. W., Davies, E. Y., 2023, arXiv e-prints, p. arXiv:2303.00008 Google Scholar
El-Badry, K., et al., 2018, MNRAS, 480, 652 CrossRefGoogle Scholar
Collaboration, Gaia et al., 2021, A&A, 649, A1 Google Scholar
Horta, D., et al., 2021a, MNRAS, 500, 1385 CrossRefGoogle Scholar
Horta, D., et al., 2021b, MNRAS, 500, 5462 CrossRefGoogle Scholar
Howes, L. M., et al., 2014, MNRAS, 445, 4241 CrossRefGoogle Scholar
Howes, L. M., et al., 2015, Nature, 527, 484 CrossRefGoogle Scholar
Howes, L. M., et al., 2016, MNRAS, 460, 884 CrossRefGoogle Scholar
Koch, A., McWilliam, A., Preston, G. W., Thompson, I. B., 2016, A&A, 587, A124 Google Scholar
Koch, A., Reichert, M., Hansen, C. J., Hampel, M., Stancliffe, R. J., Karakas, A., Arcones, A., 2019, A&A, 622, A159 Google Scholar
Kruijssen, J. M. D., et al., 2020, MNRAS, 498, 2472 CrossRefGoogle Scholar
Kunder, A., et al., 2016, ApJ, 821, L25 Google Scholar
Kunder, A., et al., 2020, AJ, 159, 270 Google Scholar
Lucey, M., et al., 2019, MNRAS, 488, 2283 CrossRefGoogle Scholar
Lucey, M., et al., 2021, MNRAS, 501, 5981 CrossRefGoogle Scholar
Lucey, M., et al., 2022, MNRAS, 509, 122 CrossRefGoogle Scholar
Ness, M., et al., 2013, MNRAS, 430, 836 CrossRefGoogle Scholar
Orkney, M. D. A., et al., 2023, arXiv e-prints, p. arXiv:2303.02147 Google Scholar
Pérez-Villegas, A., Portail, M., Gerhard, O., 2017, MNRAS, 464, L80 CrossRefGoogle Scholar
Portail, M., Wegg, C., Gerhard, O., Ness, M., 2017, MNRAS, 470, 1233 CrossRefGoogle Scholar
Queiroz, A. B. A., et al., 2023, arXiv e-prints, p. arXiv:2303.09926 Google Scholar
Reggiani, H., Schlaufman, K. C., Casey, A. R., Ji, A. P., 2020, AJ, 160, 173 CrossRefGoogle Scholar
Rix, H.-W., et al., 2022, ApJ, 941, 45 CrossRefGoogle Scholar
Savino, A., Koch, A., Prudil, Z., Kunder, A., Smolec, R., 2020, A&A, 641, A96 Google Scholar
Schiavon, R. P., et al., 2017, MNRAS, 465, 501 CrossRefGoogle Scholar
Schlaufman, K. C., Casey, A. R., 2014, ApJ, 797, 13 CrossRefGoogle Scholar
Sestito, F., et al., 2019, MNRAS, 484, 2166 CrossRefGoogle Scholar
Sestito, F., et al., 2020, MNRAS,Google Scholar
Sestito, F., et al., 2023, MNRAS, 518, 4557 CrossRefGoogle Scholar
Shen, J., Rich, R. M., Kormendy, J., Howard, C. D., De Propris, R., Kunder, A., 2010, ApJ, 720, L72 CrossRefGoogle Scholar
Sormani, M. C., Gerhard, O., Portail, M., Vasiliev, E., Clarke, J., 2022, MNRAS, 514, L1 CrossRefGoogle Scholar
Starkenburg, E., Oman, K. A., Navarro, J. F., Crain, R. A., Fattahi, A., Frenk, C. S., Sawala, T., Schaye, J., 2017a, MNRAS, 465, 2212 CrossRefGoogle Scholar
Starkenburg, E., et al., 2017b, MNRAS 471, 2587 CrossRefGoogle Scholar
Tumlinson, J., 2010, ApJ, 708, 1398 Google Scholar
de Jong, R. S., et al., 2019, The Messenger, 175, 3 Google Scholar