The frequency of occurrence of stars, particles, or other celestial objects, per specified volume of space.
- ‘Spherical harmonics were fit to the pitch and phase distributions in order to obtain fluxes from which phase space densities could be computed.’
- ‘If these are massive early-type galaxies their space density exceeds the expectations based on hierarchical clustering models.’
- ‘For a Gaussian model, the effects of multi-particles Bose-Einstein correlations on the mean phase space density are studied.’
- ‘Independent of one's redshift model, substantial changes in the luminosity function or space density of quasars and radio galaxies have occurred.’
- ‘Our study helps address the space density at low redshift, thus allowing us to get a more definitive measure of the evolution in number of these systems.’