Electron Energy Distributions at Relativistic Shock Sites: Observational Constraints from the Cygnus A Hotspots

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dc.creatorCheung, C. C.
dc.creatorStawarz, L.
dc.creatorHarris, D. E.
dc.creatorOstrowski, M.
dc.date2007-09-06
dc.date.accessioned2026-07-07T08:28:08Z
dc.date.available2026-07-07T08:28:08Z
dc.descriptionWe report new detections of the hotspots in Cygnus A at 4.5 and 8.0 microns with the Spitzer Space Telescope. Together with detailed published radio observations and synchrotron self-Compton modeling of previous X-ray detections, we reconstruct the underlying electron energy spectra of the two brightest hotspots (A and D). The low-energy portion of the electron distributions have flat power-law slopes (s~1.5) up to the break energy which corresponds almost exactly to the mass ratio between protons and electrons; we argue that these features are most likely intrinsic rather than due to absorption effects. Beyond the break, the electron spectra continue to higher energies with very steep slopes s>3. Thus, there is no evidence for the `canonical' s=2 slope expected in 1st order Fermi-type shocks within the whole observable electron energy range. We discuss the significance of these observations and the insight offered into high-energy particle acceleration processes in mildly relativistic shocks.
dc.description5 pages, 3 figures, in Extragalactic Jets: Theory and Observation from Radio to Gamma Ray, Eds. T. A. Rector and D. S. De Young
dc.identifierhttps://arxiv.org/abs/0709.0972
dc.identifierhttp://arxiv.org/abs/0709.0972
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/137507
dc.subjectAstrophysics
dc.titleElectron Energy Distributions at Relativistic Shock Sites: Observational Constraints from the Cygnus A Hotspots
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