Globular clusters (GCs) are among the oldest luminous sources in the universe, bearing witness to the
earliest stages of galaxy formation as well as their evolution to the present day. While GCs have played a
pivotal role in our understanding of the assembly of galaxies, their full potential remains unfulfilled due to
our lack of understanding of how they form. One of the largest stumbling blocks has been the anomalous
chemistry (both metallicity distributions and abundance patterns) of GCs relative to field stars within galaxy.
Here, we will turn the problem around and exploit these differences to understand the co-evolution of GCs
and their host galaxies.
Our understanding of GCs and their formation has undergone a radical change in the past two decades. First,
it is now clear that while traditionally thought of as the quintessential simple stellar populations (i.e. all stars
within a cluster have the same chemical abundances and age), globular clusters host multiple stellar
populations with spreads in He, many light elements (e.g. Na, O, Al) and even Fe in a few cases. Secondly,
GCs, once thought to only be able to form in the special conditions present in the early Universe, are now
known to be still forming today (known as Young Massive Clusters - YMCS). These two facts have opened
up a new window into the interconnectedness of GC and galaxy formation and co-evolution.
In this project we will quantitatively test current GC formation models with observations of YMCs, as well
as organise what is known of the stellar populations within GCs (e.g. abundance spreads, CMD
morphologies), providing, for the first time, a global view (i.e. which characteristics are specific to
individual GCs and which are common to all GCs). These results, when combined with what is known about
massive cluster formation in the local universe, will provide an unprecedented opportunity to use GCs to
constrain the hierarchical assembly of galaxies.
Fields of science
Funding SchemeERC-COG - Consolidator Grant
L3 5UX Liverpool
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