A view of the H-band light-element chemical patterns in Globular
  Clusters under the AGB self-enrichment scenario
  We discuss the self-enrichment scenario by AGB stars for the formation of
multiple populations in globular clusters (GCs) by analyzing data set of giant
stars observed in 9 Galactic GCs, covering a wide range of metallicities and
for which the simultaneous measurements of C, N, O, Mg, Al, Si are available.
To this aim we calculated 6 sets of AGB models, with the same chemical
composition as the stars belonging to the first generation of each GC. We find
that the AGB yields can reproduce the set of observations available, not only
in terms of the degree of contamination shown by stars in each GC but, more
important, also the observed trend with metallicity, which agrees well with the
predictions from AGB evolution modelling. While further observational evidences
are required to definitively fix the main actors in the pollution of the
interstellar medium from which new generation of stars formed in GCs, the
present results confirm that the gas ejected by stars of mass in the range
$4~\rm M_{\odot} \leq \rm M \leq 8~\rm M_{\odot}$ during the AGB phase share
the same chemical patterns traced by stars in GCs.
