Synchrotron aging in the lobes of luminous radio galaxies.
Abstract
A study has been conducted of the gradient of the 1.4-5.0 GHz spectral index observed in five luminous 3C radio galaxies. The observations have been compared with a model in which the radiation is due to an isotropic ensemble of electrons subject to synchrotron radiation losses (synchrotron aging). From such an analysis, it becomes possible to infer the age (time since acceleration) of electrons at various locations in the lobes, and consequently speeds of separation of the hot spots and lobe material. The inferred speeds are typically in the range of 10,000-30,000 km/sec. The results are consistent with the beam model, in which the lobe material is left behind by a hot spot advancing through the intergalactic medium at speeds of about 10,000 km/sec. Possible corrections to these speed estimates are discussed, and it is concluded that significantly higher speeds are possible, if not directly indicated. Finally, a number of graphs which should be useful to observers in the analysis of VLA spectral index data are discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1985
- DOI:
- 10.1086/163040
- Bibcode:
- 1985ApJ...291...52M
- Keywords:
-
- Galactic Radiation;
- Radio Galaxies;
- Synchrotron Radiation;
- Astronomical Models;
- Electron Acceleration;
- Electron Beams;
- Intergalactic Media;
- Interstellar Magnetic Fields;
- Plasma Jets;
- Radiant Flux Density;
- Very Long Base Interferometry;
- Astrophysics