2001/03/31 by G. Ghisellini, Gabriele Ghisellini, A. Celotti +1 · 4 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2001.04700.x
published as Mon.Not.Roy.Astron.Soc. 327 (2001) 739 · 5 pages, 3 figures; revised version accepted for publication in MNRAS
arxiv created 2001/06/04 · openalex publication_date 2001/11/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The recent discovery, by the Chandra satellite, that jets of blazars are strong X-ray emitters at large scales , lends support to the hypothesis that emitting plasma is still moving at highly relativistic speeds on these scales. In this case in fact the emission via inverse Compton scattering off cosmic background photons is enhanced and the resulting predicted X-ray spectrum accounts well for the otherwise puzzling observations. Here we point out another reason to favour relativistic large-scale jets, based on a minimum power argument: by estimating the Poynting flux and bulk kinetic powers corresponding to, at least, the relativistic particles and magnetic field responsible for the emission, one can derive the value of the bulk Lorentz factor for which the total power is minimized. It is found that both the inner and extended parts of the jet of PKS satisfy such a condition.