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tests:collision:gc1_archive

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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:

  1. rot_collapse_lam0.127.gz NEW! Tuesday August 20
  2. rot_collapse_lam0.168.gz NEW! Tuesday August 20
  3. rot_collapse_lam0.212.gz NEW! Tuesday August 20

visualisation

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

  1. 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].

  1. rot_collapse_fracd2.4.gz NEW! Tuesday August 20
  2. 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)

  1. What is the effect of binary stars?
  2. Is there a dynamical “smoking gun” for an intermediate mass black hole?
tests/collision/gc1_archive.1413990574.txt.gz · Last modified: 2014/10/22 15:09 by v.henault-brunet