Jets from Subparsec to Kiloparsec Scales: A Physical Connection

Abstract

The Chandra discovery of bright X-ray emission from kiloparsec-scalejets allows insight into the physical parameters of the jet flowat large scales. At the opposite extreme, extensive studies of theinner relativistic jets in blazars with multiwavelength observationsyield comparable information on subparsec scales. In the frameworkof simple radiation models for the emission regions we compare thephysical parameters of jets on these two very different scales inthe only two well-studied blazars for which large-scale emissionhas been resolved by Chandra. Notably, we find that the relativisticDoppler factors and powers derived independently at the two scalesare consistent, suggesting that the jet does not suffer severe decelerationor dissipation. Moreover, the internal equipartition pressures inthe inner jet and in the external X-ray-bright knots scale inverselywith the jet cross section as expected in the simple picture of afreely expanding jet in equipartition.