N-body representations of an analytical distribution function of the form used by McMillan and Binney (2012), evaluated in two different potentials. The distribution function represents a single “pseudo-isothermal” disc in each potential. The potentials are Milky Way-like and constructed from several spheroidal and disc like components (as in McMillan 2011).

The particles are tracers (zero mass), and the data files provide their exact positions and velocities (x,y,z,vx,vy,vz) in units of kpc and kpc/Myr (1 kpc/Myr = 977.775 km/s). Questions or comments to p.mcmillan1 (at) physics (dot) ox (dot) ac (dot) uk.

Data file 1 from first potential.

Data file 2 from second potential.

Again, N-body representations in the same two potentials - the distribution function is slightly more complicated. Data represent red clump stars (all having intrinsic G=1, V-I=1), with data including uncertainties as per those expected from Gaia, so if G>16, the radial velocity is unknown (N.B. unknown radial velocities are quoted as 0 with uncertainty given as -1)

Data format: gzipped space separated ascii, with explanation in header line (behind a # symbol):

RA(radians) dec(radians) true_parallax(mas) true_mu_a*(mas/yr) true_mu_d(mas/yr) true_vr(km/s) RA(radians) dec(radians) obs_parallax(mas) obs_mu_a*(mas/yr) obs_mu_d(mas/yr) obs_vr(km/s) err_parallax(mas) err_mu_a*(mas/yr) err_mu_d(mas/yr) err_vr(km/s) abs_G obs_G x(kpc) y(kpc) z(kpc) vx(km/s) vy(km/s) vz(km/s)

(78 Mb each, Data file 1b Data file 2b)

The Sun is placed at x=8kpc, y=0, z=0. The Sun's velocity with respect to the Galactic Centre is vR = -11.1 km/s, vz = 7.25 km/s and vphi = -258.7 km/s for model H or -249.5 km/s for model G.

If using these test data, please cite the Gaia Challenge wiki and McMillan and Binney (2012).