Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/6686
Title: Kiloparsec-scale radio emission in Seyfert and LINER galaxies
Authors: Singh, V
Ishwara-Chandra, C. H
Wadadekar, Yogesh
Beelen, Alexandre
Kharb, P
Keywords: Galaxies: active
Galaxies: Seyfert
Radio continuum: galaxies
Issue Date: 1-Jan-2015
Publisher: Oxford University Press on behalf of the Royal Astronomical Society
Citation: Monthly Notices of the Royal Astronomical Society, Vol. 446, No. 1, pp. 599-612
Abstract: Seyfert and LINER galaxies are known to exhibit compact radio emission on ∼10–100 pc scales, but larger Kiloparsec-Scale Radio structures (KSRs) often remain undetected in sub-arcsec high-resolution observations. We investigate the prevalence and nature of KSRs in Seyfert and LINER galaxies using the 1.4 GHz VLA FIRST and NVSS observations. Our sample consists of 2651 sources detected in FIRST and of these 1737 sources also have NVSS counterparts. Considering the ratio of total to peak flux density (θ = (Sint/Speak)1/2) as a parameter to infer the presence of extended radio emission we show that ≥30 per cent of FIRST-detected sources possess extended radio structures on scales larger than 1.0 kpc. The use of low-resolution NVSS observations help us to recover faint extended KSRs that are resolved out in FIRST observations and results in ≥42.5 per cent KSR sources in FIRST–NVSS sub-sample. This fraction is only a lower limit owing to the combination of projection, resolution and sensitivity effects. Our study demonstrates that KSRs may be more common than previously thought and are found across all redshifts, luminosities and radio loudness. The extranuclear radio luminosity of KSR sources is found to be positively correlated with the core radio luminosity as well as the [O III] λ5007 Å line luminosity and this can be interpreted as KSRs being powered by AGN rather than star formation. The distributions of the FIR-to-radio ratios and mid-IR colours of KSR sources are also consistent with their AGN origin. However, contribution from star formation cannot be ruled out particularly in sources with low radio luminosities.
Description: Restricted Access © Royal Astronomical Society http://dx.doi.org/10.1093/mnras/stu2260
URI: http://prints.iiap.res.in/handle/2248/6686
ISSN: 1365-2966
Appears in Collections:IIAP Publications

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