code: def dens_in_meanmatterdens(vo,ro,H=70.,Om=0.3):
      
      return dens_in_criticaldens(vo,ro,H=H)/Om
docs: NAME:
  
         dens_in_meanmatterdens
  
      PURPOSE:
  
         convert density to units of the mean matter density
  
      INPUT:
  
         vo - velocity unit in km/s
  
         ro - length unit in kpc
  
         H= (default: 70) Hubble constant in km/s/Mpc
  
         Om= (default: 0.3) Omega matter
         
      OUTPUT:
  
         conversion from units where vo=1. at ro=1. to units of the mean matter density
  
      HISTORY:
  
         2014-01-28 - Written - Bovy (IAS)