UVES analysis of red giants in the bulge globular cluster NGC 6522
  NGC 6522 is a moderately metal-poor bulge globular cluster
([Fe/H]$\sim$$-$1.0), and it is a well-studied representative among a number of
moderately metal-poor blue horizontal branch clusters located in the bulge. The
NGC 6522 abundance pattern can give hints on the earliest chemical enrichment
in the central Galaxy. The aim of this study is to derive abundances of the
light elements C and N; alpha elements O, Mg, Si, Ca, and Ti; odd-Z elements Na
and Al; neutron-capture elements Y, Zr, Ba, La, and Nd; and the r-process
element Eu. We verify if there are first- and second-generation stars: we find
clear evidence of Na-Al, Na-N, and Mg-Al correlations, while we cannot identify
the Na-O anti-correlation from our data. High-resolution spectra of six red
giants in the bulge globular cluster NGC 6522 were obtained at the 8m VLT
UT2-Kueyen telescope in FLAMES+UVES configuration. In light of Gaia data, it
turned out that two of them are non-members, but these were also analysed.
Spectroscopic parameters were derived through the excitation and ionisation
equilibrium of FeI and FeII lines from UVES spectra. The abundances were
obtained with spectrum synthesis. The present analysis combined with previous
UVES results gives a mean radial velocity of vrhel = -15.62+-7.7 km.s-1 and a
metallicity of [Fe/H] = -1.05+-0.20 for NGC 6522. Mean abundances of alpha
elements for the present four member stars are enhanced with
  [O/Fe]=+0.38, [Mg/Fe]=+0.28, [Si/Fe]=+0.19, and [Ca/Fe]=+0.13, together with
the iron-peak element [Ti/Fe]=+0.13, and the r-process element
[Eu/Fe]=+0.40.The neutron-capture elements Y, Zr, Ba, and La show enhancements
in the +0.08 < [Y/Fe] < +0.90, 0.11 < [Zr/Fe] < +0.50, 0.00 < [Ba/Fe] < +0.63,
0.00 < [La/Fe] < +0.45, and -0.10 < [Nd/Fe] < +0.70 ranges. We also discuss the
spread in heavy-element abundances.
