A growing number of recent observations have revealed that the Galactic globular cluster ( GC ) \omega Cen is not the only GC that shows abundance spread in heavy elements ( e.g. , Fe ) .
In order to understand the origin of the Galactic GCs with heavy element abundance spread ( “ HEAS ” ) , we investigate the formation processes of massive GCs ( MGCs ) with masses larger than 10 ^ { 6 } { M } _ { \odot } in gas-rich dwarf galaxies interacting and merging with the very young Galaxy .
We find that massive and compact stellar clumps with masses larger than 10 ^ { 6 } { M } _ { \odot } , which can be regarded as progenitors of MGCs , can form from massive gas clumps that are developed through merging of gaseous regions initially at different radii and thus with different metallicities .
Therefore it is inevitable that MGCs formed in dwarfs have HEAS .
The abundance spread in each individual MGC depends on the radial metallicity gradient of the host dwarf such that it can be larger for the steeper metallicity gradient .
For example , MGCs formed in a dwarf with a central metallicity of [ Fe/H ] = -1.1 and the radial gradient of \sim - 0.2 dex kpc ^ { -1 } can have the abundance spread of \Delta { [ Fe / H ] } \sim 0.2 .
The simulated MGCs appear to be significantly flattened owing to their dissipative formation from gas disks of their host dwarfs .
Based on these results , we discuss possibly diverse formation mechanisms for the Galactic GCs such as M22 , M54 , NGC 2419 , \omega Cen , and Terzan 5 .