====== Collisional Systems ======

===== Overview =====

**Working group coordinators:** Mark Gieles, Vincent Henault-Brunet (m.gieles, v.henault-brunet [at] surrey.ac.uk)

[[:tests:collision:GC4| Gaia Challenge 4 (Stockholm) Collisional systems discussion and results]].


You will find here some challenges based on data from collisional N-body models. These mock data are designed to mimic collisional systems like star/globular clusters.

A summary of Gaia Challenge II from the Collisional systems working group can be found [[:tests:collision:GC2_archive|here]]. Preliminary results from the Gaia Challenge I workshop in Surrey are [[:tests:collision:GC1_archive|archived here]].

Mock datasets for all challenges can be downloaded [[:tests:collision:mock_data|here]].

Additional mock datasets and ideas for new challenges are listed [[:tests:collision:new_challenges|here]].

Links to some useful fitting and analysis tools are listed in the [[:tests:collision:tools|Tools section]].


Ideas and goals for the Gaia Challenge III workshop (Barcelona) are listed [[:tests:collision:GC3|here]].


Throughout the Gaia Challenge I-III workshops, we have tackled four specific challenges:

**1. Single mass clusters: the interplay of anisotropy and tides (Zocchi et al. in prep)**

**2. Clusters with a mass spectrum: testing the validity of multi-mass models (Peuten et al. in prep)**

**3. Observational biases (Sollima et al. 2015)**

**4. Method comparison: Jeans modelling vs Distribution-function based models**

Many of the challenges make use of LIMEPY ([[http://arxiv.org/abs/1508.02120|Gieles & Zocchi 2015]]) developed in the context of the Gaia Challenge.