2008ApJ...681...84A

Recent theoretical work has pointed out that the transition layer between a jet and the medium surrounding it may be more complex than previously thought. Under physically realizable conditions, the transverse profile of the Lorentz factor in the boundary layer can be nonmonotonic, displaying the absolute maximum where the flow is faster than at the jet spine, followed by a steep falloff. Likewise, the rest-mass density reaches an absolute minimum (coincident with the maximum in Lorentz factor) and then grows until it reaches the external medium value. Such behavior is in contrast to the standard monotonic decline of the Lorentz factor (from a maximum value at the jet central spine) and the corresponding increase of the rest-mass density (from the minimum reached at the jet core). We study the emission properties of the aforementioned anomalous shear layer structures in kiloparsec-scale jets, aiming to show observable differences with respect to conventional monotonic and smooth boundary layers.