First Evidence of Globular Cluster Formation from the Ejecta of Prompt
  Type Ia Supernovae
  Recent spectroscopic observations of globular clusters (GCs) in the Large
Magellanic Cloud (LMC) have discovered that one of the intermediate-age GC, NGC
1718 with [Fe/H]=-0.7 has an extremely low [Mg/Fe] ratio of ~-0.9. We propose
that NGC 1718 was formed from the ejecta of type Ia supernovae (SNe Ia) mixed
with very metal-poor ([Fe/H] <-1.3) gas about ~ 2 Gyr ago. The proposed
scenario is shown to be consistent with the observed abundances of Fe-group
elements such as Cr, Mn, and Ni. In addition, compelling evidence for
asymptotic giant branch stars playing a role in chemical enrichment during this
GC formation is found. We suggest that the origin of the metal-poor gas is
closely associated with the efficient gas-transfer from the outer gas disk of
the Small Magellanic Cloud to the LMC disk. We anticipate that the outer part
of the LMC disk contains field stars exhibiting significantly low [Mg/Fe]
ratios, formed through the same process as NGC 1718.
