KMOS Spectroscopic Follow-up of 16 Star Cluster Candidates of the Sagittarius Dwarf Galaxy

@misc{obasi2026kmos,
  title = {{KMOS Spectroscopic Follow-up of 16 Star Cluster Candidates of the Sagittarius Dwarf Galaxy}},
  author = {C. O. Obasi and J. G. Fernández-Trincado and D. Minniti and M. Gómez and E. R. Garro and R. K. Saito and J. Alonso-García and V. D. Ivanov and J. Corral-Santana and A. Luna and Z. Guo and R. Kurtev and J. Borissova and V. Fermiano and C. Morris and B. Dias and C. Caceres and S. Saroon and J. B. Pullen and P. I. A. Rodríguez Cuevas and M. Lad and S. Federle and I. Petralia and P. W. Lucas and D. Bhadrakumar Sindhu and P. Esteves and M. G. Navarro and T. Palma and L. D. Baravalle and E. O. Schmidt and D. Galdeano and M. V. Alonso and J. L. Nilo Castellón and A. -N. Chené and J. Osses},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.28374},
  eprint = {2610.28374},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.28374},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - KMOS Spectroscopic Follow-up of 16 Star Cluster Candidates of the Sagittarius Dwarf Galaxy
AU  - C. O. Obasi
AU  - J. G. Fernández-Trincado
AU  - D. Minniti
AU  - M. Gómez
AU  - E. R. Garro
AU  - R. K. Saito
AU  - J. Alonso-García
AU  - V. D. Ivanov
AU  - J. Corral-Santana
AU  - A. Luna
AU  - Z. Guo
AU  - R. Kurtev
AU  - J. Borissova
AU  - V. Fermiano
AU  - C. Morris
AU  - B. Dias
AU  - C. Caceres
AU  - S. Saroon
AU  - J. B. Pullen
AU  - P. I. A. Rodríguez Cuevas
AU  - M. Lad
AU  - S. Federle
AU  - I. Petralia
AU  - P. W. Lucas
AU  - D. Bhadrakumar Sindhu
AU  - P. Esteves
AU  - M. G. Navarro
AU  - T. Palma
AU  - L. D. Baravalle
AU  - E. O. Schmidt
AU  - D. Galdeano
AU  - M. V. Alonso
AU  - J. L. Nilo Castellón
AU  - A. -N. Chené
AU  - J. Osses
PY  - 2026
DA  - 2026/10/20
PB  - arXiv
DO  - 10.48550/arxiv.2610.28374
UR  - https://arxiv.org/abs/2610.28374
AB  - The Sagittarius (Sgr) dwarf spheroidal galaxy hosts several known globular clusters and numerous additional cluster candidates identified toward its crowded central regions. Establishing the nature of these candidates is difficult because apparent spatial and astrometric structure can arise from the underlying Sgr population. We investigate sixteen Minni stellar-cluster candidates with KMOS spectroscopy to determine whether the observed stars are compatible with Sgr and whether any candidate field shows evidence for a distinct stellar system. We analyse H-band KMOS spectra of 341 targets from the VVVX-GalCen Spectroscopic Survey, deriving radial velocities (RVs) and empirical metallicities. We compare these with an independent Sgr spectroscopic sample and use VVVX photometry and Gaia DR3 astrometry to test for localized stellar excesses relative to local control fields. Of the 341 KMOS targets, 256 (75%) have RVs within the adopted Sgr interval, and their metallicities broadly overlap the Sgr comparison population. No field shows statistically compelling kinematic evidence for a distinct system after accounting for the multiple candidates examined. Minni 329 shows the strongest spatial excess, but this is not significant after multiple-testing correction and is not accompanied by significant central concentration. The KMOS targets predominantly trace the Sgr population, but Sgr compatibility alone does not confirm the individual candidates as distinct stellar clusters. None of the sixteen fields can be confirmed as a separate stellar system with the present data, although this does not establish that the original candidates are spurious. Deeper imaging and larger spectroscopic samples are required to determine their physical nature.
ER  -