APOGEE view of the globular cluster NGC 6544
  The second phase of the APOGEE survey is providing near-infrared,
high-resolution, high signal-to-noise spectra of stars in the halo, disk, bar
and bulge of the Milky Way. The near-infrared spectral window is especially
important in the study of the Galactic bulge, where stars are obscured by the
dust and gas of the disk in its line-of-sight. We present a chemical
characterisation of the globular cluster NGC 6544 with high-resolution
spectroscopy. The characterisation of the cluster chemical fingerprint, given
its status of "interloper" towards the Galactic bulge and clear signatures of
tidal disruption in its core is crucial for future chemical tagging efforts.
Cluster members were selected from the DR16 of the APOGEE survey, using
chemo-dynamical criteria of individual stars. A sample of 23 members of the
cluster was selected. An analysis considering the intra-cluster abundance
variations, known anticorrelations is given. According to the RGB content of
the cluster, the iron content and $\alpha$-enhancement are [Fe/H] $= -1.44 \pm
0.04$ dex and [$\alpha$/Fe] $= 0.20 \pm 0.04$ dex, respectively. Cluster
members show a significant spread in [Fe/H] and [Al/Fe] that is larger than
expected based on measurement errors. An [Al/Fe] spread, signal of an Mg-Al
anticorrelation is observed and used to constraint the cluster mass budget,
along with C, N, Mg, Si, K, Ca, and Ce element variations are discussed. Across
all the analysed evolutionary stages (RGB and AGB), about $\sim2/3$ (14 out of
23) show distinct chemical patterns, possibly associated with second-generation
stars.
