THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. III. ANALYSIS OF 3CRR OBJECTS

Dicken, D, Tadhunter, C, Axon, David, Robinson, A, Morganti, R and Kharb, P (2010) THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. III. ANALYSIS OF 3CRR OBJECTS. Astrophysical Journal, 722 (2). pp. 1333-1341. ISSN 0004-637X

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Abstract

We present Spitzer photometric data for a complete sample of 19 low-redshift (z < 0.1) 3CRR radio galaxies as part of our efforts to understand the origin of the prodigious mid-to far-infrared (MFIR) emission from radio-loud active galactic nuclei (AGNs). Our results show a correlation between AGN power (indicated by [O III]lambda 5007 emission line luminosity) and 24 mu m luminosity. This result is consistent with the 24 mu m thermal emission originating from warm dust heated directly by AGN illumination. Applying the same correlation test for 70 mu m luminosity against [O III] luminosity we find this relation to suffer from increased scatter compared to that of 24 mu m. In line with our results for the higher-radio-frequency-selected 2 Jy sample, we are able to show that much of this increased scatter is due to heating by starbursts that boost the far-infrared emission at 70 mu m in a minority of objects (17%-35%). Overall this study supports previous work indicating AGN illumination as the dominant heating mechanism for MFIR emitting dust in the majority of low-to-intermediate redshift radio galaxies (0.03 < z < 0.7), with the advantage of strong statistical evidence. However, we find evidence that the low-redshift broad-line objects (z < 0.1) are distinct in terms of their positions on the MFIR versus [O III] correlations.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: David Axon
Date Deposited: 06 Feb 2012 20:32
Last Modified: 07 Mar 2017 06:07
URI: http://sro.sussex.ac.uk/id/eprint/26453

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