Title: Spectroscopic study of the elusive globular cluster ESO452-SC11 and its surroundings,
Abstract: Globular clusters (GCs) are amongst the oldest objects in the Galaxy and play
a pivotal role in deciphering its early history. We present the first
spectroscopic study of the GC ESO452-SC11 using the AAOmega spectrograph at
medium resolution. Given the sparsity of this object and high degree of
foreground contamination due to its location toward the bulge, few details are
known for this cluster: there is no consensus of its age, metallicity, or its
association with the disk or bulge. We identify 5 members based on radial
velocity, metallicity, and position within the GC. Using spectral synthesis,
accurate abundances of Fe and several $\alpha$-, Fe-peak, neutron-capture
elements (Si,Ca,Ti,Cr,Co,Ni,Sr,Eu) were measured. Two of the 5 cluster
candidates are likely non-members, as they have deviant Fe abundances and
[$\alpha$/Fe] ratios. The mean radial velocity is 19$\pm$2 km s$^{-1}$ with a
low dispersion of 2.8$\pm$3.4 km s$^{-1}$, in line with its low mass. The mean
Fe-abundance from spectral fitting is $-0.88\pm0.03$, with a spread driven by
observational errors. The $\alpha$-elements of the GC candidates are marginally
lower than expected for the bulge at similar metallicities. As spectra of
hundreds of stars were collected in a 2 degree field around ESO452-SC11,
detailed abundances in the surrounding field were measured. Most non-members
have higher [$\alpha$/Fe] ratios, typical of the nearby bulge population. Stars
with measured Fe-peak abundances show a large scatter around Solar values,
though with large uncertainties. Our study provides the first systematic
measurement of Sr in a Galactic bulge GC. The Eu and Sr abundances of the GC
candidates are consistent with a disk or bulge association. Our calculations
place ESO452 on an elliptical orbit in the central 3 kpc of the bulge. We find
no evidence of extratidal stars in our data. (Abridged)