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The NV/CIV ratio in high redshift radio galaxies

R. A. E. Fosbury·J. Vernet·M. Villar-Martin·M. H. Cohen·A. Cimatti·S. di Serego Alighieri
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Abstract

Deep Keck spectropolarimetry has been obtained of a sample of powerful radio galaxies with $z \sim 2.5 \pm 1$. 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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R. A. E. Fosbury, J. Vernet, M. Villar-Martin, M. H. Cohen, A. Cimatti, S. di Serego Alighieri. 1999-01-11. The NV/CIV ratio in high redshift radio galaxies. https://arxiv.org/abs/astro-ph/9901115

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