NICMOS Imaging of High-Redshift Radio Galaxies
Abstract
We have obtained near-infrared (1.6 micron) images of 11 powerful 3CR radio galaxies at redshifts 0.8 < z < 1.8 using NICMOS on board HST. The high angular resolution permits a detailed study of galaxy morphology in these systems at rest-frame optical wavelengths, where starlight dominates over the extended, aligned UV continuum. The NICMOS morphologies are mostly symmetric and are consistent with dynamically relaxed, elliptical host galaxies dominated by a red, mature stellar population. The aligned structures are sometimes faintly visible, and nuclear point sources may be present in a few cases which manifest the ``unveiled'' AGN that is obscured from view at optical wavelengths. Our observations are consistent with the hypothesis that the host galaxies of z ~ 1-2 radio galaxies are similar to modern-day gE galaxies. Their sizes are typical of gE galaxies but smaller than present-day cD and brightest cluster galaxies, and their surface brightnesses are higher, as expected given simple luminosity evolution.
Keywords
Cite
@article{arxiv.astro-ph/9909210,
title = {NICMOS Imaging of High-Redshift Radio Galaxies},
author = {A. Zirm and A. Dey and M. Dickinson and P. J. McCarthy and P. Eisenhardt and S. G. Djorgovski and H. Spinrad and S. A. Stanford and W. van Breugel},
journal= {arXiv preprint arXiv:astro-ph/9909210},
year = {2007}
}
Comments
4 pages, 2 figures; to appear in the proceedings of "The Hy-Redshift Universe: Galaxy Formation and Evolution at High Redshift", held in Berkeley, June 21-24, 1999