Abstract
| Garro |
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| Where are the super metal-rich Bulge globular clusters? - Revealing an inconsistency |
| We catalogue 45 recently discovered Bulge Globular Clusters (GCs). Our main goal is to understand what we can learn if they are included into the current Milky Way (MW) GC system. We use tools like metallicity distribution (MD), luminosity function (LF), [Mg/Fe]-[Fe/H] diagram, and age distribution. We consider three samples: new GCs, known GCs, and then we merge them, upgrading the MWGC system. We find a double-peaked GCs' LF, which shows an elongated faint end tail. The GC's MD display a bimodal trend. We construct the MD for field stars (FS) sample, and we notice that several FS show [Fe/H]>0, while none of the GCs fall into this metallicity range.We construct the age-metallicity diagram, noting that the old and metal-poor population is represented by GCs, while the young and metal-rich one corresponds to FS.We recognise three star formation phases (initial burst, star forming quenching and secular evolution) in the [Mg/Fe]-[Fe/H] diagram. GCs are grouped in the initial phase, whereas the other two phases are represented by FS. We conclude that the bimodality of LF suggests that many GCs have been accreted during merging events. This is supported by the MD, which indicates that the metal-poor component is mainly the contribution due to the tidal disruption of dwarf-like objects whereas the metal-rich population is related to the bulge/disk's formation. The inconsistency between GC and FS samples should be sought in the evolutionary difference between these two populations. |