Special Session SS10  29 June 2021

Extragalactic Globular Clusters with upcoming wide-field space-based surveys

Aims and scope

Globular Clusters (GCs) are ubiquitous in galaxies through space and time. Thus, these systems are among the fundamental building blocks of galaxies and trace their assembly history. They have always played a crucial role in astrophysics. The properties of GCs exhibit strong galaxy-to-galaxy differences, which result from differences in their evolutionary histories. Thus, to approach a more complete picture of GC formation, they have to be studied in a variety of galaxies with different masses, environments, and formation histories. Understanding how star cluster luminosity functions, physical sizes, and contents vary as a function of the environment in which they were formed will be crucial for our understanding of GCs themselves and to use them as fossil records of previous galaxy merger events.

The first space-based imaging surveys that will cover large fractions of the sky, such as EUCLID and the Roman Space Telescope, will launch in the next few years. These surveys will enable us to identify extragalactic GCs far beyond the distances where it is currently feasible to cover large areas of the sky. Thanks to their depth and spatial resolution, and to the synergies implemented with ground-based surveys, the wide-field space-based surveys are expected to increase the number of known extragalactic GCs dramatically. The combined benefits of a great homogeneity and of morphological information will lead to a large range of applications in GC science. This conference aims at bringing together the extragalactic GC community and experts of each survey, to specifically discuss and explore the future avenues that these exceptional data sets will provide in this area of investigation.

In particular we plan to explore how these surveys will expand the use of Globular Clusters as kinematic tracers of former accretion events as well as tracers of the dark matter content of their parent galaxies. These wide-field imaging surveys that have a high enough spatial resolution to resolve GCs will mark a leap in detection efficiency and thus how well we can use them as tracers. Using GCs as dynamical tracers will highly depend on the synergies of these space based surveys with ground based spectroscopic surveys which will be explored in this session.

A second focus topic will be how the extension of precision photometry to the GCs of more distant galaxies will shed light on cluster formation processes and on the peculiarities of their stellar populations. The surveys will help determine how GC color-color relations and age-metallicity distributions depend on the environment these objects live in. By considering the integrated light signature of multiple stellar populations across the optical and near-IR spectrum, new insights may be gained on issues such as the abundance anti-correlations and UV-upturn in massive elliptical galaxies.

As a third cornerstone, the meeting will provide a platform for theorists to share their predictions for the formation and co-evolution of galaxies and their GC populations. Many of these predictions on Globular Cluster population assembly will be testable for the first time with the upcoming larger datasets.


1. How will space-based deep wide-field surveys shape extragalactic GC astronomy?

2. What are the synergies of space based surveys with ground based photometric and spectroscopic surveys to use GCs as large scale dynamical tracers?

3. How will these large scale surveys and their precision photometry help us determine how the stellar populations and abundances of GCs depend on their environment?

4. What models of GC and Galaxy co-evolution are available as counterparts to these observations and what are the new testable parameters?


Invited speakers

  • Patrick Côté
  • Ariane Lançon
  • Dougal Mackey
  • Marta Reina-Campos
  • Laura Sales
  • Rubén Sánchez-Janssen

Scientific organisers

  • Karina Voggel (Co-Chair)
  • William Chantereau (Co-Chair)
  • Eric Peng
  • Annette Ferguson
  • Søren Larsen
  • Ariane Lançon


  • karina.voggel @ astro.unistra.fr
  • wchantereau @ unistra.fr
    • Updated on Wed Jan 27 18:15:59 CET 2021