At the first meeting the Team Members will be joined by Enrica Iodice and Junior Researchers: Callum Bellhouse, Jesse Golden-Marx, Lucas Kimmig, Rossella Ragusa.
The program is available at this Google doc page: https://docs.google.com/document/d/14MSjlti9h3g1wI8laQYufR9pxEAjyo410l_tg0_5zrU/edit?usp=sharing
We will address the key technical issues that hamper progress on ICL research. These technical issues are:
Connecting observations to simulations:
The direct comparison of ICL properties derived from simulations and observations is fraught with issues because it involves comparing quantities that are measured/derived using completely different methods. A robust comparison of the two requires realistic forward-modelling of simulation data to faithfully reproduce the biases of observational facilities. Furthermore, standardised metrics must be used to measure the ICL in both the observational and the realistic synthetic images.
Understanding biases:
The various simulations and observations from differing facilities suffer from differing biases. Observationally, this can include astrophysical foregrounds and surface brightness limits. Simulations, on the other hand, are intrinsically limited by their finite resolution and approximate modelling of astrophysical processes. To cross-compare different observations and simulations we must reconcile these biases and define metrics that allow us to circumvent these differences.
At this first meeting, we have two goals:
(1) to compare the predicted ICL content, evolution, and properties from different simulations to elucidate the factors driving the differences. Once these differences are understood, we will agree on a robust predictive framework of ICL properties from the simulations.
(2) to explore the ability of various algorithms to recover ICL from simulated observations and define standardised metrics to recover ICL properties from broad-band images such as those expected from Euclid and Roman.
The meeting will be structured so that new collaborations are established which will progress and implement the ideas developed during the first meeting in the interim period before the second meeting (for example, conducting analyses of simulated data sets using observational methods).
The meeting is intended as being highly interactive and hands-on. While there will be talks from the participants, much of the time will be designated for open discussions and for subgroups to work together on specific topics.
From the two meetings and interim discussions we aim to produce:
● A robust predictive framework of ICL properties derived from the simulations.
● Standardised metrics to recover ICL properties from broad-band images that allow us to robustly compare results from different facilities.
● A library of simulated clusters with predicted ICL structures and properties (e.g., metallicity, age) for clusters spanning a range of dynamical states, masses, and redshifts.
● Codes for generating synthetic observations of ICL that include the biases of each of the new observational facilities using the simulated cluster library.
● We anticipate there will be a peer-reviewed paper describing these outputs and we expect the subsequent work of our team will directly lead to at least a dozen papers on new ICL discoveries and their theoretical interpretation over the coming years.