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The NV/CIV ratio in high redshift radio galaxies

1999/01/11 by R. A. E. Fosbury, Fosbury, R. A. E., J. Vernet +10
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/9901115

6 pages. pdf viewgraphs available at: http://ecf.hq.eso.org/~rfosbury/research/preprints/chemev98/ To appear in "ESO Conference on Chemical Evolution from Zero to High Redshift", Garching, Germany, October 14-16, 1998. ESO Astrophysics Symposia. Eds. J Walsh and M Rosa, Springer

Abstract

Deep Keck spectropolarimetry has been obtained of a sample of powerful radio galaxies with z ∼ 2.5 ± 1. In addition to a clear 2200Ådust scattering/extinction signature and an inverse correlation between the degree of continuum polarization and the Lyman-αemission line strength (relative to C IV), we find an intriguing positive correlation between the N~V/C IV ratio and the polarization. The line ratio, which varies by almost a dex amongst objects having a very similar ionization state, is most likely to indicate an abundance ratio. We speculate that the correlation with polarization represents a connection between nitrogen enhancement and dust production following a major starburst event connected with the birth of the quasar.

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