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Herschel-ATLAS/GAMA: What determines the far-infrared properties of radio galaxies?

Virdee, J. S. and Hardcastle, M. J. and Rawlings, S. and Rigopoulou, D. and Mauch, T. and Jarvis, M. J. and Verma, A. and Smith, D. J. B. and Heywood, I. and White, S. V. and Baes, M. and Cooray, A. and de Zotti, G. and Eales, S. and Michałowski, M. J. and Bourne, N. and Dariush, A. and Dunne, L. and Hopwood, R. and Ibar, E. and Maddox, S. and Smith, M. W. L. and Valiante, E. (2013) Herschel-ATLAS/GAMA: What determines the far-infrared properties of radio galaxies? Monthly Notices of the Royal Astronomical Society, 432 (1). pp. 609-625. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20130708-131008421

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Abstract

We perform a stacking analysis of Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) data in order to obtain isothermal dust temperatures and rest-frame luminosities at 250 μm (L_250), for a well-defined sample of 1599 radio sources over the H-ATLAS Phase 1/Galaxy and Mass Assembly (GAMA) area. The radio sample is generated using a combination of NRAO VLA Sky Survey data and K-band United Kingdom Infrared Telescope Deep Sky Survey–Large Area Survey data, over the redshift range 0.01 < z < 0.8. The far-infrared (FIR) properties of the sample are investigated as a function of 1.4-GHz luminosity, redshift, projected radio-source size and radio spectral index. In order to search for stellar-mass-dependent relations, we split the parent sample into those sources which are below and above 1.5 L∗_(K). After correcting for stellar mass and redshift, we find no relation between the 250-μm luminosity and the 1.4-GHz radio luminosity of radio active galactic nuclei. This implies that a galaxy's nominal radio luminosity has little or no bearing on the star formation rate (SFR) and/or dust mass content of the host system, although this does not mean that other variables (e.g. radio source size) related to the jets do not have an effect. The L_250 of both the radio detected and non-radio-detected galaxies (defined as those sources not detected at 1.4 GHz but detected in the Sloan Digital Sky Survey with r′ < 22) rises with increasing redshift. Compact radio sources (<30 kpc) are associated with higher 250 μm luminosities and dust temperatures than their more extended (>30 kpc) counterparts. The higher dust temperature suggests that this may be attributed to enhanced SFRs in compact radio galaxies, but whether this is directly or indirectly due to radio activity (e.g. jet-induced or merger-driven star formation) is as yet unknown. For matched samples in L_K and g′–r′, sub-1.5 L∗_K and super-1.5 L∗_K radio-detected galaxies have 0.89±0.18 and 0.49±0.12 times the 250 μm luminosity of their non-radio-detected counterparts. Thus, while no difference in L_250 is observed in sub-1.5 L∗_K radio-detected galaxies, a strong deficit is observed in super-1.5 L∗_K radio-detected galaxies. We explain these results in terms of the hotter, denser and richer halo environments massive radio galaxies maintain and are embedded in. These environments are expected to quench the cold gas and dust supply needed for further star formation and therefore dust production. Our results indicate that all massive radio galaxies (>1.5 L∗_K) may have systematically lower FIR luminosities (∼25 per cent) than their colour-matched non-radio-detected counterparts. Finally, no relation between radio spectral index and L_250 is found for the subset of 1.4-GHz radio sources with detections at 330 MHz.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1093/mnras/stt488DOIArticle
http://mnras.oxfordjournals.org/content/432/1/609PublisherArticle
ORCID:
AuthorORCID
Cooray, A.0000-0002-3892-0190
de Zotti, G.0000-0003-2868-2595
Additional Information:© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 March 18. Received 2013 February 20; in original form 2012 October 23. First published online: April 15, 2013. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. We thank the anonymous referee for comments which have helped improve the paper. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. US participants in H-ATLAS acknowledge support provided by NASA through a contract issued from JPL. GAMA is a joint European-Australasian project based around a spectroscopic campaign using the Anglo-Australian Telescope. The GAMA input catalogue is based on data taken from the SDSS and the UKIRT Infrared Deep Sky Survey. Complementary imaging of the GAMA regions is being obtained by a number of independent survey programmes including GALEX MIS, VST KIDS, VISTA VIKING, WISE, HATLAS, GMRT and ASKAP providing UV to radio coverage. GAMA is funded by the STFC (UK), the ARC (Australia), the AAO and the Participating Institutions. The GAMA website is http://www.gama-survey.org/. JSV thanks the STFC and RAL for a studentship. MJJ acknowledges support from an RCUK fellowship.
Funders:
Funding AgencyGrant Number
NASA/JPLUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Australian Research CouncilUNSPECIFIED
Australian Astronomical Observatory (AAO)UNSPECIFIED
RAL studentshipUNSPECIFIED
Research Councils UK (RCUK)UNSPECIFIED
Subject Keywords:galaxies: active; infrared: galaxies; radio continuum: galaxies
Record Number:CaltechAUTHORS:20130708-131008421
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20130708-131008421
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39250
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:08 Jul 2013 23:12
Last Modified:24 Oct 2017 22:25

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