Observational Effects of Anomalous Boundary Layers in Relativistic Jets

TL;DR

This paper investigates the complex boundary layer structures in relativistic jets, revealing non-monotonic Lorentz factor profiles and their impact on observable emission properties, contrasting with traditional models.

Contribution

It introduces the concept of non-monotonic boundary layers in relativistic jets and analyzes their potential observational signatures, advancing understanding of jet boundary dynamics.

Findings

Non-monotonic Lorentz factor profiles can occur in jet boundary layers.

Anomalous shear layers produce distinct emission signatures.

Observable differences from standard boundary layer models are identified.

Abstract

Recent theoretical work has pointed out that the transition layer between a jet an 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 non-monotonic, displaying the absolute maximum where the flow is faster than at the jet spine, followed by an steep fall off. 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 a 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.