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Optical spectroscopy of radio galaxies in the 7C Redshift Survey

Chris J. Willott·Steve Rawlings·Katherine M. Blundell·Mark Lacy·Gary J. Hill·Susan E. Scott
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Abstract

We present optical spectroscopy of all 49 radio galaxies in the 7C-I and 7C-II regions of the 7C Redshift Survey (7CRS). The low-frequency (151 MHz) selected 7CRS sample contains all sources with flux-densities S_151 > 0.5 Jy in three regions of the sky; 7C-I and 7C-II were chosen to overlap with the 5C6 and 5C7 surveys respectively, and cover a total sky area of 0.013 sr. The sample has been completely identified and spectroscopy of the quasars and broad-lined radio galaxies has been presented in Willott et al. (1998). Only seven of the radio galaxies do not have redshift determinations from the spectroscopy, giving a redshift completeness for the sample of >90%. The median redshift of the 7CRS is 1.1. We present a composite 0.2<z<0.8 7CRS radio galaxy spectrum and investigate the strengths of the 4000 Angstrom breaks in these radio galaxies. We find an anti-correlation between the 4000 Angstrom break strength and emission line luminosity, indicating that departures from old elliptical galaxy continuum shapes are most likely due to non-stellar emission associated with the active nucleus.

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Chris J. Willott, Steve Rawlings, Katherine M. Blundell, Mark Lacy, Gary J. Hill, Susan E. Scott. 2002-05-29. Optical spectroscopy of radio galaxies in the 7C Redshift Survey. https://doi.org/10.1046/j.1365-8711.2002.05718.x

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