The origin of the critical point of a cylindrical liquid jet, first maximum of the stability curve, is not fully understood so far. In a previous experimental investigation, three different jet regimes of atomization were defined according to the influence of the gas density on the jet critical velocity. Whether a jet is in a given regime was found to be a function of a parameter rho (G)*, equivalent to a density In the present investigation, the relevance of this parameter is considered and jet atomization processes are studied through the analysis of the evolution of the drop size distribution,t in the vicinity of the critical condition. A (rho (G)*, Z) map is derived from the analysis of a large amount of experimental results found in the literature. This map is of practical interest, as it helps in presupposing the behavior of a liquid jet. The analysis of the drop size distribution reveals that the instability that develops when the critical velocity is reached may be a subcritical or a supercritical instability, according to the jet regime of atomization. When a subcritical instability develops, the disintegration process is controlled by capillary instability even for velocities greater than the critical velocity and the breakup length varies according to the initial conditions. It was found that the development of such instabilities has no effect on the relative drop size distribution width, which seems therefore to he mainly a function of the perturbation growth process. When a supercritical instability develops, the df development of the critical point is due to the action of the aerodynamic forces, which increases the temporal growth rate of the instability as the velocity increases.