Inskip, K.J., Best, P.N., Longair, M.S. et al. (1 more author) (2005) HST and UKIRT imaging observations of z ∼ 1 6C radio galaxies – II. Galaxy morphologies and the alignment effect. Monthly Notices of the Royal Astronomical Society, 359 (4). pp. 1393-1414. ISSN 0035-8711
Abstract
Powerful radio galaxies often display enhanced optical/ultraviolet emission regions, elongated and aligned with the radio jet axis. The aim of this series of papers is to investigate separately the effects of radio power and redshift on the alignment effect, together with other radio galaxy properties. In this second paper, we present a deeper analysis of the morphological properties of these systems, including both the host galaxies and their surrounding aligned emission. The host galaxies of our 6C subsample are well described as de Vaucouleurs ellipticals, with typical scale sizes of ∼10 kpc. This is comparable to the host galaxies of low-z radio sources of similar powers, and also the more powerful 3CR sources at the same redshift. The contribution of nuclear point source emission is also comparable, regardless of radio power. The 6C alignment effect is remarkably similar to that seen around more powerful 3CR sources at the same redshift in terms of extent and degree of alignment with the radio source axis, although it is generally less luminous. The bright, knotty features observed in the case of the z ∼ 1 3CR sources are far less frequent in our 6C subsample; neither do we observe such strong evidence for evolution in the strength of the alignment effect with radio source size/age. However, we do find a very strong link between the most extreme alignment effects and emission-line region properties indicative of shocks, regardless of source size/age or power. In general, the 6C alignment effect is still considerably stronger than that seen around lower redshift galaxies of similar radio powers. Cosmic epoch is clearly just as important a factor as radio power: although aligned emission is observed on smaller scales at lower redshifts, the processes which produce the most extreme features simply no longer occur, suggesting considerable evolution in the properties of the extended haloes surrounding the radio source.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2005 RAS. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | galaxies : active; galaxies : evolution; galaxies : ISM; radio continuum : galaxies |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Apr 2019 08:40 |
Last Modified: | 12 Apr 2019 08:40 |
Status: | Published |
Publisher: | Oxford University Press (OUP) for Royal Astronomical Society |
Refereed: | Yes |
Identification Number: | 10.1111/j.1365-2966.2005.08981.x |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:144864 |