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arXiv · 1509.06800

GTC optical imaging of extremely red 5C radio galaxies at high redshift

A. Humphrey·M. Villar-Martín·P. Lagos
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Abstract

We investigate the nature of seven unusual radio galaxies from the 5C catalogue that were previously known to have extremely red R-K colours, and for which emission lines were previously found to be weak or absent in their optical spectra. We present and discuss u, g, or r images of these radio galaxies, obtained using the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the Gran Telescopio Canarias (GTC). We have detected all seven targets in our g-band imaging. Their optical emission is extended, and we tentatively detect a radio-optical alignment effect in this sample. A subset of our sample (three sources) shows broad-band spectral energy distributions that flatten out near the wavelength range of the g-band, implying a dominant contribution there due to young stars and/or scattered or reprocessed radiation from the active nucleus.

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A. Humphrey, M. Villar-Martín, P. Lagos. 2015-09-22. GTC optical imaging of extremely red 5C radio galaxies at high redshift. https://doi.org/10.1051/0004-6361%2F201526411

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