This is an old revision of the document!
Table of Contents
Archive
Preliminary results from Gaia Challenge 1 workshop
Challenge 1: Equal mass clusters in a tidal field
| All Stars | 1000 stars | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Cluster | Method | $M$ | $r_{\rm c}$ | $r_{\rm h}$ | $r_{\rm J}$ | $M$ | $r_{\rm c}$ | $r_{\rm h}$ | $r_{\rm J}$ |
| 1 | Isotropic King (linear dens) | $0.919$ | $1.190$ | ||||||
| Isotropic King (log dens) | $0.046$ | $1.61$ | |||||||
| Anisotropic Michie King | $0.027$ | $1.55$ | |||||||
| $f_\nu$ | $1.082$ | $1.134$ | |||||||
| 2 | Isotropic King (linear dens) | $0.875$ | $1.322$ | ||||||
| Isotropic King (log dens) | $0.04$ | $1.752$ | |||||||
| Anisotropic Michie King | $0.026$ | $1.618$ | |||||||
| $f_\nu$ | $1.023$ | $1.314$ | |||||||
| 3 | Isotropic King (linear dens) | $0.227$ | $6.839$ | ||||||
| Isotropic King (log dens) | $0.28$ | $7.655$ | |||||||
| Anisotropic Michie King | |||||||||
| $f_\nu$ | $0.259$ | $8.225$ | |||||||
| Cluster | Plots | |
|---|---|---|
| 1 | Isotropic King vs $f_\nu$ |  |
| Anisotropic Michie King |  |
|
| 2 | Isotropic King vs $f_\nu$ |  |
| Anisotropic Michie King |  |
|
| 3 | Isotropic King vs $f_\nu$ |  |
| Anisotropic Michie King |  |
Other possible challenges
Pal 5 model from Andreas Kuepper in streams section
Same analyses as in Challenge 2 and 3, but with cluster on eccentric orbit and “polluting” stars from tidal tails. The models posted in the streams section were not evolved with stellar evolution and for a Hubble time, but Andreas sent me files for that. Will upload them if there is interest.
Models with initial rotation
Different models with angular momentum are within the group: collapsing spheres, cold fractal collapse, cluster mergers.
Collapse of homogeneous spheres with angular momentum
Below snapshots of 3 cold(ish) collapses of homogeneous spheres with angular momentum. Initial virial ratios and angular momentum were taken from the 3 models described in Gott (1972). The models contain 2e5 stars, a Kroupa IMF between 0.1 and 100 Msun and snapshots are at t=30 [NBODY]. The amount of rotation is quantified with Peebles $\lambda$ parameter in the title:
- rot_collapse_lam0.127.gz NEW! Tuesday August 20
- rot_collapse_lam0.168.gz NEW! Tuesday August 20
- rot_collapse_lam0.212.gz NEW! Tuesday August 20
Mergers
Merger between 2 clusters of equal mass, equal containing 1e5 stars, a Kroupa IMF between 0.1 and 100 Msun. The initial orbit of the cluster pair had zero energy and different angular momentum. The
- rot_merger_lam0.128.gz NEW! Tuesday August 20
For both collapse and mergers collapse contain:
| $M$ | $X$ | $Y$ | $Z$ | $V_x$ | $V_y$ | $V_z$ |
|---|---|---|---|---|---|---|
| [$M_\odot$] | [NBODY] | [NBODY] | ||||
Collapse of non-homogeneous spheres with angular momentum
(Based on simulations ran by Anna Lisa Varri, see Ref1 Ref2)
Below snapshots of two cold(ish) collapses of isolated spheres with N=64k, equal mass stars, non-homogeneous initial density distribution (fractal dimension D = 2.8, 2.4, as in the file name), and approximate solid-body rotation. The configurations are characterized by the same initial values of virial ratio and global angular momentum as in the homogeneous case #3 (with $\lambda=0.212$). The simulations have been performed with STARLAB and the snapshots are taken at T=20 [NBODY].
- rot_collapse_fracd2.4.gz NEW! Tuesday August 20
- rot_collapse_fracd2.8.gz NEW! Tuesday August 20
The file header contains: N, T, coordinates and velocities of the center of mass. The file format is as follow:
| $ID$ | $M$ | $X$ | $Y$ | $Z$ | $V_x$ | $V_y$ | $V_z$ |
|---|---|---|---|---|---|---|---|
| [NBODY] | [NBODY] | [NBODY] | |||||
More ideas (but no mock data for these yet)
- What is the effect of binary stars?
- Is there a dynamical “smoking gun” for an intermediate mass black hole?