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The Astronomical Journal Volume 117 Number 3 Create an alert RSS this journal

Daniel Stern et al. 1999 The Astronomical Journal 117 1122 doi:10.1086/300770

New High-Redshift Radio Galaxies from the MIT-Green Bank Catalog*

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Daniel Stern1, Arjun Dey2,5, Hyron Spinrad1, Leslie Maxfield1, Mark Dickinson2,6, David Schlegel3 and Rosa A. Gonzßlez4

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Abstract References Cited By

We present optical identifications and redshifts for 17 new high-redshift radio sources. Fifteen of these sources are radio galaxies; the remaining two are high-redshift, steep-spectrum, radio-loud quasars. These objects were discovered as part of an ongoing study of compact (θ < 10''), moderately steep spectrum (α > 0.75,Sν ∝ ν-α) sources from the MIT–Green Bank (MG) radio catalog (S5 GHz gtrsim 50 mJy). Spectra for the optical counterparts were obtained at the W. M. Keck Telescopes and are among the optically faintest radio galaxies thus far identified. Redshifts range between 0.3 and 3.6, with 13 of the 17 at redshifts greater than 1.5. Combining these new radio galaxies with two published MG radio galaxy spectra, we synthesize a composite MG radio galaxy spectrum and discuss the properties of these galaxies in comparison with other, more powerful, radio galaxies at similar redshifts. We suggest a radio power–ionization state relation.


Footnote
*  Based on observations obtained at the W. M. Keck Observatory, Lick Observatory, and the MDM Observatory. The Keck Observatory is operated as a scientific partnership among the University of California, the California Institute of Technology, and the National Aeronautics and Space Administration and was made possible by the generous financial support of the W. M. Keck Foundation.
Keywords

early universe; galaxies: active; galaxies: distances and redshifts; galaxies: evolution


Dates

Issue 3 (1999 March)

Received 1998 September 2, accepted for publication 1998 November 20



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