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high resolution Milky Way dark matter halos simulated on NASA's Columbia and ORNL's Jaguar supercomputers |
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The data on this page is freely available. When using the z=0 data in publications or proposals, please refer to this web site, to astro-ph/0611370 for VL-1 and to astro-ph/0805.1244 for VL-2.
If you use the evolutionary tracks or the peakVmax values, please cite also astro-ph/0703337. Raw data and other halo properties are available on request (diemand 'at' ucolick 'dot' org).
Halos and subhalos in the high resolution region of the via lactea runs were identified using the 6DFOF halo and subhalo finder (see astro-ph/0603250 and astro-ph/0611370).
VL-2 data
redshift zero subhalo propertiesvltwosubs.txt contains all 20,048 halos and subhalos (including the host halo), which had a peak circular velocity larger than 4 km/s at some time. (Over 150,000 smaller systems can be identified in vl-2, but their abundances and properties are affected by resolution effects and they are therefore not included here.)
| column | units | comments |
|---|---|---|
| GCdistance | kpc | distance from the galactic center |
| peakVmax | km/s | peak of Vmax over the full subhalo history |
| Vmax | km/s | the maximum of the circular velocity vc=sqrt[GM(<r)/r] |
| rVmax | kpc | radius of maximal circular velocity |
| Mtidal | Msun | mass enclosed within the tidal radius |
| rtidal | kpc | tidal radius (for isolated halos, this radius is set to roughly r_200 instead) |
| rel_pos(3) | kpc | x,y and z coordinates relative to the galactic center |
| rel_vel(3) | km/s | x,y and z components of the velocity relative to the galactic center |
| M <300pc | Msun | mass enclosed within 300 pc* |
| M <600pc | Msun | mass enclosed within 600 pc* |
| (*) : note that the tidal radii of some subhalos are smaller than 300 or 600 pc. | ||
random sample of particles at reshift zero
This file contains a random subset of 100'000 dark matter particles selected from the z=0 snapshot within 800 kpc of the galactic center. Positions and velocites relative to the galactic center are given. To get the same total mass each of the particles in this subsample would represent a mass of 2.823e7 solar masses.
evolutionary tracks of halos and subhalos
Time evolution of properties for the same 20,048 objects as above. There is one file for each property, and each line describes one halo, form snapshot 400; z=0 (first column) back in time to snapshot 3; z=27.54 (last column). 27 snapshots were and analyzed, for list of snapshot number vs. expansion factor and redshift click here. Zeros mean that no progenitor was found for this halo at that time. Negative size values (Vmax,Rvmax,Mtidal,Rtidal) indicate that this object overlaped with a different, larger halo at that time.
| property | units | comments |
|---|---|---|
| GCdistance | physical kpc | distance from the galactic center (or from its main progenitor for z>0) |
| Vmax | physical km/s | the maximum of the circular velocity vc=sqrt[GM(<r)/r] |
| rVmax | physical kpc | radius of maximal circular velocity |
| Mtidal | Msun | mass within the tidal radius |
| rtidal | physical kpc | tidal radius |
| x, y, z | 40 comoving Mpc | x,y and z comoving coordinates (host halo coordinates are given in the 2nd to last line) |
| vx, vy, vz | 1008.8 comoving km/s | time derivatives of the comoving coordinates. add H(z)*Dx when converting to physical relative velocities (H_0 = 73 km/s/Mpc). |
The tracks given above only contain systems which are still resolved at z=0. Similar tracks for the 20'000 largest systems identifed at z=4.56 are available here. The file formats are similar as above, but note that the ordering of columns is reversed: Now the first column corresponds to step 3 (z=27.54) and the last column to snapshot 400 (z=0).
VL-1 data
redshift zero subhalo propertiesvlonesubs.txt contains all 6,553 halos and subhalos (but not the host halo), which had a peak circular velocity larger than 5 km/s at some time. (Over 40,000 smaller systems can be identified in vl-1, but their abundances and properties are significantly affected by resolution effects and they are therefore not included here.)
| column | units | comments |
|---|---|---|
| GCdistance | kpc | distance from the galactic center |
| peakVmax | km/s | peak of Vmax over the full subhalo history |
| Vmax | km/s | the maximum of the circular velocity vc=sqrt[GM(<r)/r] |
| rVmax | kpc | radius of maximal circular velocity |
| Mtidal | Msun | mass enclosed within the tidal radius |
| rtidal | kpc | tidal radius (for isolated halos, this radius is set to roughly r_200 instead) |
| rel_pos(3) | kpc | x,y and z coordinates relative to the galactic center |
| rel_vel(3) | km/s | x,y and z components of the velocity relative to the galactic center |
| new: | ||
| M <300pc | Msun | mass enclosed within 300 pc* (lower limits only, VL-1 does not fully resolve this quantity) |
| M <600pc | Msun | mass enclosed within 600 pc* |
| (*) : note that the tidal radii of some subhalos are smaller than 300 or 600 pc. | ||
new: random sample of particles at reshift zero
This file contains a random subset of 100'000 dark matter particles selected from the z=0 snapshot within 800 kpc of the galactic center. Positions and velocites relative to the galactic center are given. To get the same total mass each of the particles in this subsample would represent a mass of 2.247e7 solar masses.
evolutionary tracks of halos and subhalos
Time evolution of properties for the same 6553 objects as above. There is one file for each property, and each line describes one halo, form snapshot 400; z=0 (first column) back in time to snapshot 6; z=16.12 (last column). Only even snapshot numbers were stored and analyzed, i.e. there are 198 columns corresponding to different times. Zeros mean that no progenitor was found for this halo at that time. For list of snapshot number vs. expansion factor and redshift click here.
| property | units | comments |
|---|---|---|
| GCdistance | physical kpc | distance from the galactic center (or from its main progenitor for z>0) |
| CorrectedGCdistance | physical kpc | as above, but for those snapshots closest to a pericenter passage the corrected pericenter distance is given |
| Vmax | physical km/s | the maximum of the circular velocity vc=sqrt[GM(<r)/r] |
| rVmax | physical kpc | radius of maximal circular velocity |
| Mtidal | Msun | mass within the tidal radius |
| rtidal | physical kpc | tidal radius |
| x, y, z | 90 comoving Mpc | x,y and z comoving coordinates (host halo coordinates are given here) |
| vx, vy, vz | 2279.61 comoving km/s | time derivatives of the comoving coordinates. add H(z)*Dx when converting to physical relative velocities (H_0 = 73 km/s/Mpc). |
The tracks given above only contain systems which are still resolved at z=0. Similar tracks for the 10'000 largest systems identifed at z=4.47 are available here. The file formats are similar as above, but note that the ordering of columns is reversed: Now the first column corresponds to step 6 (z=16.12) and the last column to snapshot 400 (z=0).
evolution of the mass distribution around the host halo
This ASCII file gives the mass in spheres of fixed physical radii around the main halo center. Each line contains masses enclosed within 51 spheres [mass unit=1.0779e+17 solar masses]. A list of their radii in physical kpc is given here. The first line is for snapshot number 6 (z=16.1), the last line corresponds to snapshot 400, which is at z=0. For list of snapshot number vs. expansion factor and redshift click here.
Postitions and velocities of the host halo center at each snapshot are given here.
last updated: March 20, 2009, by J. Diemand
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This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License,
please acknowledge the via lactea project and/or its authors wherever material from this web site is used. | ||||