TY - JOUR
T1 - The chemical compositions of accreted and in situ galactic globular clusters according to SDSS/APOGEE
AU - Horta, Danny
AU - Schiavon, Ricardo P.
AU - MacKereth, J. Ted
AU - Beers, Timothy C.
AU - Fernández-Trincado, José G.
AU - Frinchaboy, Peter M.
AU - García-Hernández, D. A.
AU - Geisler, Doug
AU - Hasselquist, Sten
AU - Jonsson, Henrik
AU - Lane, Richard R.
AU - Majewski, Steven R.
AU - Mészáros, Szabolcs
AU - Bidin, Christian Moni
AU - Nataf, David M.
AU - Roman-Lopes, Alexandre
AU - Nitschelm, Christian
AU - Vargas-González, J.
AU - Zasowski, Gail
PY - 2020/4
Y1 - 2020/4
N2 - Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic association, we break the sample down into eight separate groups and examine how the kinematics-based classification maps into chemical composition space, considering only α (mostly Si and Mg) elements and Fe. Our results show that (i) the loci of both in situ and accreted subgroups in chemical space match those of their field counterparts; (ii) GCs from different individual accreted subgroups occupy the same locus in chemical space. This could either mean that they share a similar origin or that they are associated with distinct satelliteswhich underwent similar chemical enrichment histories; (iii) the chemical compositions of the GCs associated with the low orbital energy subgroup defined by Massari and collaborators is broadly consistent with an in situ origin. However, at the low-metallicity end, the distinction between accreted and in situ populations is blurred; (iv) regarding the status of GCs whose origin is ambiguous, we conclude the following: the position in Si-Fe plane suggests an in situ origin for Liller 1 and a likely accreted origin for NGC 5904 and NGC 6388. The case of NGC 288 is unclear, as its orbital properties suggest an accretion origin, its chemical composition suggests it may have formed in situ.
AB - Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic association, we break the sample down into eight separate groups and examine how the kinematics-based classification maps into chemical composition space, considering only α (mostly Si and Mg) elements and Fe. Our results show that (i) the loci of both in situ and accreted subgroups in chemical space match those of their field counterparts; (ii) GCs from different individual accreted subgroups occupy the same locus in chemical space. This could either mean that they share a similar origin or that they are associated with distinct satelliteswhich underwent similar chemical enrichment histories; (iii) the chemical compositions of the GCs associated with the low orbital energy subgroup defined by Massari and collaborators is broadly consistent with an in situ origin. However, at the low-metallicity end, the distinction between accreted and in situ populations is blurred; (iv) regarding the status of GCs whose origin is ambiguous, we conclude the following: the position in Si-Fe plane suggests an in situ origin for Liller 1 and a likely accreted origin for NGC 5904 and NGC 6388. The case of NGC 288 is unclear, as its orbital properties suggest an accretion origin, its chemical composition suggests it may have formed in situ.
KW - Galaxy: formation
KW - Globular Clusters; Galaxy: evolution
UR - http://www.scopus.com/inward/record.url?scp=85085360963&partnerID=8YFLogxK
U2 - 10.1093/mnras/staa478
DO - 10.1093/mnras/staa478
M3 - Article
AN - SCOPUS:85085360963
SN - 0035-8711
VL - 493
SP - 3363
EP - 3378
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -