Inspection of the energy and angular momentum values. Left: total specific energy E (in units of 10⁴ km s⁻¹) versus the square of the specific angular momentum L (in units of 10⁹ kpc² km² s⁻²) at the present time; dotted line represents the relation for a particle of negligible mass on a circular orbit. Right: E against the specific angular momentum in the Cartesian x-direction of a Galactocentric reference frame, L_x (in units of 10³ kpc km s⁻¹); the red solid line at L_x = 0 is for reference only. In both panels, symbols and colours as in Fig. 3; error bars for the uncertain systems, which are large, are not shown for clarity.