Description
Organisers: Jessica Doppel, Stephane Werner, Mathilde Jauzac
In the era of next-generation telescopes such as JWST and Euclid, high-resolution, visible-by-eye images of the diffuse intracluster light (ICL) of galaxy clusters are becoming increasingly abundant. This component of galaxy clusters is comprised of stars, including star clusters, stellar remnants, gas, and dust that do not belong to the individual cluster galaxies, but rather to the overall cluster itself. The ICL has been positioned as an extremely valuable tool for understanding many properties of galaxy clusters, e.g. their dynamics, accretion histories, and shapes. Indeed, the existence of ICL itself provides a testing ground for the hierarchical formation scenario predicted by our current cosmological paradigm. By tracing the assembly history of galaxy clusters, ICL components serve as tracers of galaxy cluster dynamics. It can thus be used to trace their dark matter distribution of clusters and act as a new dark matter probe.
Combining the incoming wealth of ICL observations and the push towards higher resolution galaxy cluster simulations has the potential to lead the field not only towards a more detailed understanding of our current datasets but also towards answering still-open and key questions: How do we quantify ICL? What is the best way to measure ICL? How does ICL evolve with time? How can ICL be used to probe dark matter? We aim for this session to address these open questions and identify scientific gaps in this emerging research field.
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09/07/2025, 16:15Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
Multiwavelength data on the most observed galaxy clusters allows for comprehensive mass modelling of each component: dark matter, intra-cluster gas, the galaxy's baryons, and the intra-cluster stars. Such modelling could be done with a combination of multiple mass probes, constraining the total mass of each individual baryonic component, but no method for such modelling has been released.
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Tutku Kolcu (The University of Nottingham)09/07/2025, 16:25Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
Galaxy clusters form through hierarchical merging, with the intracluster light (ICL) serving as a luminous tracer of these processes. The distribution and morphology of ICL provide critical insights into the evolution of galaxy clusters. Moreover, the stripped stars that form the ICL are bound to underlying gravitational potential of the cluster, thus making the ICL a valuable probe for the...
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Joseph Butler (University of Nottingham)09/07/2025, 16:35Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
The diffuse stellar component of galaxy clusters known as intracluster light (ICL) has been proposed as an observable tracer of the clusterโs dark matter (DM) halo. Investigating the energetics of the intracluster stars is essential for understanding how they are linked to the underlying DM distribution and, consequently, assessing the reliability of the ICL as a DM tracer. In this talk, I...
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09/07/2025, 16:45Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
Intracluster light (ICL) appears in observations as a faint, diffuse glow at the heart of galaxy clusters, composed primarily of stars that drift freely within the cluster's gravitational potential, untethered to any galaxy. To unravel the story of its early formation, we must journey back in time to when galaxy clusters were still assembling. In this work, we use observations and simulations...
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Garreth Martin (University of Nottingham)09/07/2025, 16:55Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
Cosmological hydrodynamical simulations are widely used to make predictions for the intracluster light (ICL), but the impact of numerical resolution on the tidal stripping of stars remains unclear. In particular, a simulation's ability to accurately capture the stellar disruption of satellite galaxies depends on both mass resolution and force softening, which influence the structure of...
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Harley Brown (University of Nottingham)09/07/2025, 17:05Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
Although there is a developing understanding of the mechanisms by which the diffuse stellar component of galaxy clusters termed the intracluster light (ICL) is formed, no strong consensus has yet been reached on which objects the stars of the ICL are primarily sourced from. We have investigated ICL assembly in the Horizon-AGN simulation (a cosmological hydrodynamical simulation), and in this...
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Jessica Doppel (Durham University)09/07/2025, 17:15Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
We present a post-processing catalog of globular clusters (GCs) for the 39 most massive galaxy groups and clusters (M$_{200} = [5\times 10^{12} - 2\times 10^{14}] \ \rm M_{\odot}$) in the TNG50 simulation. We tag GCs particles to all galaxies with stellar masses $M_{\odot} \geq 5\times 10^{6} \ \rm M_{\odot}$, and we calibrate the total mass of the GC system to reproduce the observed GC...
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Jaewon Yoo (Korea Institute for Advanced Study)09/07/2025, 17:25Intracluster light: illuminating the next generation of galaxy cluster scienceTalk
The self-interacting dark matter (SIDM) model has garnered increasing attention as a potential solution to discrepancies between dark matter-only simulations and observations in small scales. SIDM predicts distinct tidal interaction histories compared to the cold dark matter (CDM) model, leading to differences in the evolution and distribution of intracluster light (ICL). In this study, we...
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