2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/145119We describe very accurate imaging of radio spectral index for the inner jets in three FR I radio galaxies. Where the jets first brighten, there is a remarkably small dispersion around a spectral index of 0.62. This is also the region where bright X-ray emission is detected. Further from the nucleus, the spectral index flattens slightly to 0.50 - 0.55 and X-ray emission, although still detectable, is fainter relative to the radio. The brightest X-ray emission from the jets is therefore not associated with the flattest radio spectra, but rather with some particle-acceleration process whose characteristic energy index is 2.24. The change in spectral index occurs roughly where our relativistic jet models require rapid deceleration. Flatter-spectrum edges can be seen where the jets are isolated from significant surrounding diffuse emission and we suggest that these are associated with shear.5 pages, 3 figures, to appear in Extragalactic Jets: Theory and Observation from Radio to Gamma Ray, T. A. Rector and D. S. De Young (eds.), ASP Conference SeriesAstrophysicstext