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Astron. Astrophys. 334, 799-804 (1998)
Nature of 60µm emission in 3C 47, 3C 207 and 3C 334
Ilse M. van Bemmel 1,
Peter D. Barthel 1 and
Min S. Yun 2
1 Kapteyn Astronomical Institute, P.O. Box 800,
9700 AV Groningen, The Netherlands
2 NRAO VLA, P.O. Box 0, Socorro, NM, USA
Received 2 February 1998 / Accepted 16 March 1998
Abstract
We try to explain the unusually high far-infrared emission seen by IRAS in the double-lobed radio-loud quasars 3C 47, 3C 207 and 3C 334. High resolution cm-mm observations were carried out to determine their radio core spectra, which are subsequently extrapolated to the far-infrared in order to determine the strength of the synchrotron far-infrared emission. The extrapolated flux densities being considerably lower than the observed values, a significant nonthermal far-infrared component is unlikely in the case of 3C 47 and 3C 334. However, this component could be responsible for the far-infrared brightness of 3C 207. Our analysis demonstrates that nonthermal emission cannot readily account for the difference between quasars and radio galaxies in the amount of their far-infrared luminosity. On the other hand, a significant role for this mechanism is likely; full sampling of the mm-submm spectral energy distributions is needed to address the issue quantitatively.
Key words: infrared:
galaxies 
radio continuum:
galaxies
quasars:
general
quasars: individual: 3C 47; 3C 207; 3C 334
Send offprint requests to: Ilse M. van Bemmel
Contents
- 1. Introduction
- 2. Sample description, observations and data reduction
- 2.1. VLA cm observations
- 2.2. OVRO 3mm observations
- 2.3. Archive and literature data
- 3. Results and spectral fits
- 4. Analysis and discussion
- 4.1. Non-thermal FIR
- 4.2. Thermal FIR
- 5. Conclusions and future research
- Acknowledgements
- References
© European Southern Observatory (ESO) 1998
Online publication: June 2, 1998
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