TY - JOUR
T1 - A deep dive into the Type II globular cluster NGC 1851
AU - Dondoglio, E.
AU - Milone, A. P.
AU - Marino, A. F.
AU - D’Antona, F.
AU - Cordoni, G.
AU - Legnardi, M. V.
AU - Lagioia, E. P.
AU - Jang, S.
AU - Ziliotto, T.
AU - Carlos, M.
AU - Dell’Agli, F.
AU - Karakas, A.
AU - Mohandasan, A.
AU - Osborn, Z.
AU - Tailo, M.
AU - Ventura, P.
N1 - Funding Information:
We thank the anonymous referee for the valuable comments. This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 - Research and Innovation Framework Programme (Grant Agreement ERC-StG 2016, No. 716082 ‘GALFOR’, PI: Milone, http://progetti.dfa.unipd.it/GALFOR ) and from the European Union’s Horizon 2020 - Research and Innovation Framework Programme under the Marie Sklodowska-Curie grant agreement no. 101034319 and from the European Union – NextGenerationEU, beneficiary: Ziliotto. SJ acknowledges support from the NRF of Korea (2022R1A2C3002992 and2022R1A6A1A03053472). APM, MT, and ED acknowledge support from MIUR through the FARE project R164RM93XW SEMPLICE (PI: Milone). APM and ED have been supported by MIUR under PRIN program 2017Z2HSMF (PI: Bedin). FD and PV acknowledge the support received from the PRIN INAF 2019 grant ObFu 1.05.01.85.14 (‘Building up the halo: chemo-dynamical tagging in the age of large surveys’, PI. S. Lucatello) and the INAF-GTO-GRANTS 2022 (‘Understanding the formation of globular clusters with their multiple stellar generations’, PI. A. F. Marino). ZO acknowledges that this research was supported by an Australian Government Research Training Program (RTP) Scholarship. AK and ZO were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.
Publisher Copyright:
© 2023 Oxford University Press. All rights reserved.
PY - 2023/12
Y1 - 2023/12
N2 - About one-fifth of the Galactic globular clusters (GCs), dubbed Type II GCs, host distinct stellar populations with different heavy elements abundances. NGC 1851 is one of the most studied Type II GCs, surrounded by several controversies regarding the spatial distribution of its populations and the presence of star-to-star [Fe/H], C+N+O, and age differences. This paper provides a detailed characterization of its stellar populations through Hubble Space Telescope (HST), ground-based, and Gaia photometry. We identified two distinct populations with different abundances of s-process elements along the red-giant branch (RGB) and the subgiant branch (SGB) and detected two subpopulations among both s-poor (canonical) and s-rich (anomalous) stars. To constrain the chemical composition of these stellar populations, we compared observed and simulated colours of stars with different abundances of He, C, N, and O. It results that the anomalous population has a higher CNO overall abundance compared to the canonical population and that both host stars with different light-element abundances. No significant differences in radial segregation between canonical and anomalous stars are detected, while we find that among their subpopulations, the two most chemical extremes are more centrally concentrated. Anomalous and canonical stars show different 2D spatial distributions outside ∼3 arcmin, with the latter developing an elliptical shape and a stellar overdensity in the north-east direction. We confirm the presence of a stellar halo up to ∼80 arcmin with Gaia photometry, tagging 14 and 5 of its stars as canonical and anomalous, respectively, finding a lack of the latter in the south/south-east field.
AB - About one-fifth of the Galactic globular clusters (GCs), dubbed Type II GCs, host distinct stellar populations with different heavy elements abundances. NGC 1851 is one of the most studied Type II GCs, surrounded by several controversies regarding the spatial distribution of its populations and the presence of star-to-star [Fe/H], C+N+O, and age differences. This paper provides a detailed characterization of its stellar populations through Hubble Space Telescope (HST), ground-based, and Gaia photometry. We identified two distinct populations with different abundances of s-process elements along the red-giant branch (RGB) and the subgiant branch (SGB) and detected two subpopulations among both s-poor (canonical) and s-rich (anomalous) stars. To constrain the chemical composition of these stellar populations, we compared observed and simulated colours of stars with different abundances of He, C, N, and O. It results that the anomalous population has a higher CNO overall abundance compared to the canonical population and that both host stars with different light-element abundances. No significant differences in radial segregation between canonical and anomalous stars are detected, while we find that among their subpopulations, the two most chemical extremes are more centrally concentrated. Anomalous and canonical stars show different 2D spatial distributions outside ∼3 arcmin, with the latter developing an elliptical shape and a stellar overdensity in the north-east direction. We confirm the presence of a stellar halo up to ∼80 arcmin with Gaia photometry, tagging 14 and 5 of its stars as canonical and anomalous, respectively, finding a lack of the latter in the south/south-east field.
KW - stars: abundances
KW - stars: Population II
KW - techniques: photometric
UR - http://www.scopus.com/inward/record.url?scp=85175177231&partnerID=8YFLogxK
U2 - 10.1093/mnras/stad2950
DO - 10.1093/mnras/stad2950
M3 - Article
AN - SCOPUS:85175177231
SN - 0035-8711
VL - 526
SP - 2960
EP - 2976
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -