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N-body models from Elena D'Onghia

Snapshots provided by Elena D'Onghia from her simulations in, which have 100 million disk particles. Ask Jo Bovy to get these from a USB stick. The simulation and data consists of snapshots at 0 Myr (initial conditions), 250 Myr, and 1 Gyr (snap_000.hdf5, snap_005.hdf5, snap_020.hdf5).

The galaxy model consists of an Hernquist halo with total mass of 9.5×10^11 Msun computed at a radius of 160 kpc. The halo is simulated with a rigid potential. The concentration of the halo is adopted to be c=9 for an Hernquist profile which is approximately like c=12 for a NFW profile. The spin parameter of the halo is lambda=0.033. This galaxy contains a live stellar disk and a little live bulge that made more stable the disk:


The disk fraction is: Mdisk/Mhalo=0.04 The scale length is 2.5 kpc. We introduced perturbers corotating with the stellar disk as softened particles (the total number of perturbers is 1000 and each has a mass of 9.5×10^5 Msun so that the total mass of the perturbers is ~ 9.5×10^8 Msun which is ~2.5% of the total disk mass). In the run we fixed the softening of the perturbes with size of giant a molecular cloud: ~100 pc. In the initial setup the vertical thickness of the disk is setup z0=0.1 of the scale length. Number of particles in the disk= 100 millions. In gadget snapshot stellar disk particles are type 2.


The bulge fraction is: 0.01. The size is 0.1 of the disk scale length. Number of particles in the bulge is : 10 millions. In gadget snapshot bulge particles are type 3.

The particles that mimic the perturbers are 1000 and in gadget are type 4.

Q parameter is initially set up to be larger than 1.3 at all radii.

Publication policy

If using these test data, please cite the Gaia Challenge wiki and

tests/discs/mockdonghia.txt · Last modified: 2014/11/03 09:10 by kawata