TY - JOUR
T1 - Studying Binary Systems in Omega Centauri with MUSE
T2 - I. Detection of Spectroscopic Binaries
AU - Wragg, F.
AU - Kamann, S.
AU - Saracino, S.
AU - Latour, M.
AU - Dreizler, S.
AU - Martens, S.
AU - Seth, A.
AU - Vaz, D.
AU - van de Ven, G.
N1 - © 2024 The Author(s).
PY - 2024/11/1
Y1 - 2024/11/1
N2 - NGC 5139 ($\omega$ Cen), is the closest candidate of a Nuclear Star Cluster that has been stripped of its host galaxy in the Milky Way. Despite extensive studies through the last decades, many open questions about the cluster remain, including the properties of the binary population. In this study we use MUSE multi-epoch spectroscopy to identify binary systems in $\omega$ Cen. The observations span 8 years, with a total of 312 248 radial velocity measurements for 37 225 stars. Following the removal of known photometric variables, we identify 275 stars that show RV variations, corresponding to a discovery fraction of 1.4$\pm$0.1%. Using dedicated simulations, we find that our data is sensitive to 70$\pm$10% of the binaries expected in the sample, resulting in a completeness-corrected binary fraction of 2.1$\pm$0.4% in the central region of $\omega$ Cen. We find similar binary fractions for all stellar evolutionary stages covered by our data, the only notable exception being the blue straggler stars, which show an enhanced binary fraction. We also find no distinct correlation with distance from the cluster centre, indicating a limited amount of mass segregation within the half-light radius of $\omega$ Cen.
AB - NGC 5139 ($\omega$ Cen), is the closest candidate of a Nuclear Star Cluster that has been stripped of its host galaxy in the Milky Way. Despite extensive studies through the last decades, many open questions about the cluster remain, including the properties of the binary population. In this study we use MUSE multi-epoch spectroscopy to identify binary systems in $\omega$ Cen. The observations span 8 years, with a total of 312 248 radial velocity measurements for 37 225 stars. Following the removal of known photometric variables, we identify 275 stars that show RV variations, corresponding to a discovery fraction of 1.4$\pm$0.1%. Using dedicated simulations, we find that our data is sensitive to 70$\pm$10% of the binaries expected in the sample, resulting in a completeness-corrected binary fraction of 2.1$\pm$0.4% in the central region of $\omega$ Cen. We find similar binary fractions for all stellar evolutionary stages covered by our data, the only notable exception being the blue straggler stars, which show an enhanced binary fraction. We also find no distinct correlation with distance from the cluster centre, indicating a limited amount of mass segregation within the half-light radius of $\omega$ Cen.
KW - Astrophysics - Astrophysics of Galaxies
U2 - 10.1093/mnras/stae2333
DO - 10.1093/mnras/stae2333
M3 - Article
SN - 0035-8711
VL - 535
SP - 781
EP - 792
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -