Far-infrared observations of radio quasars and FR II radio galaxies

Y. Shi, George H. Rieke, D. C. Hines, G. Neugebauer, M. Blaylock, J. Rigby, E. Egami, K. D. Gordon, A. Alonso-Herrero

Research output: Contribution to journalArticle

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Abstract

We report MIPS photometry of 20 radio-loud quasars and galaxies at 24 and 70 μm (and of five at 160 μm). We combine this sample with additional sources detected in the far-infrared by IRAS and ISO for a total of 47 objects, including 23 steep-spectrum type I AGNs: radio-loud quasars and broad-line radio galaxies; and 24 type II AGNs: narrow-line and weak-line FR II radio galaxies. Of this sample, the far-infrared emission of all but 3C 380 appears to be dominated by emission by dust heated by the AGN and by star formation. The AGN appears to contribute more than 50% of the far-infrared luminosity in most of the sources. It is also expected that the material around the nucleus is optically thin in the far-infrared. Thus, the measurements at these wavelengths can be used to test the orientation-dependent unification model. As predicted by the model, the behavior of the sources is consistent with the presence of an obscuring circumnuclear torus; in fact, we find that it may still have significant optical depth at 24 μm. In addition, as expected for the radio-loud quasars, there is a significant correlation between the low-frequency radio (178 MHz) and the 70 μm emission, two presumably isotropic indicators of nuclear activity. This result is consistent with the simple unified scheme. However, there is a population of radio galaxies that are underluminous at 70 μm compared with the radio-loud quasars and hence are a challenge to the simple unified model.

Original languageEnglish (US)
Pages (from-to)88-99
Number of pages12
JournalAstrophysical Journal
Volume629
Issue number1 I
DOIs
StatePublished - Aug 10 2005

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radio galaxies
quasars
radio
Infrared Astronomy Satellite
optical thickness
photometry
star formation
dust
luminosity
galaxies
low frequencies
nuclei
wavelengths
optical depth
wavelength

Keywords

  • Galaxies: active
  • Infrared: galaxies
  • Quasars: general

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Shi, Y., Rieke, G. H., Hines, D. C., Neugebauer, G., Blaylock, M., Rigby, J., ... Alonso-Herrero, A. (2005). Far-infrared observations of radio quasars and FR II radio galaxies. Astrophysical Journal, 629(1 I), 88-99. https://doi.org/10.1086/431344

Far-infrared observations of radio quasars and FR II radio galaxies. / Shi, Y.; Rieke, George H.; Hines, D. C.; Neugebauer, G.; Blaylock, M.; Rigby, J.; Egami, E.; Gordon, K. D.; Alonso-Herrero, A.

In: Astrophysical Journal, Vol. 629, No. 1 I, 10.08.2005, p. 88-99.

Research output: Contribution to journalArticle

Shi, Y, Rieke, GH, Hines, DC, Neugebauer, G, Blaylock, M, Rigby, J, Egami, E, Gordon, KD & Alonso-Herrero, A 2005, 'Far-infrared observations of radio quasars and FR II radio galaxies', Astrophysical Journal, vol. 629, no. 1 I, pp. 88-99. https://doi.org/10.1086/431344
Shi Y, Rieke GH, Hines DC, Neugebauer G, Blaylock M, Rigby J et al. Far-infrared observations of radio quasars and FR II radio galaxies. Astrophysical Journal. 2005 Aug 10;629(1 I):88-99. https://doi.org/10.1086/431344
Shi, Y. ; Rieke, George H. ; Hines, D. C. ; Neugebauer, G. ; Blaylock, M. ; Rigby, J. ; Egami, E. ; Gordon, K. D. ; Alonso-Herrero, A. / Far-infrared observations of radio quasars and FR II radio galaxies. In: Astrophysical Journal. 2005 ; Vol. 629, No. 1 I. pp. 88-99.
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