Emission-Line Properties of MG2016+112: A Luminous Type-2 Quasar at High Redshift

T. Yamada; S. Yamazaki; M. Hattori; G. Soucail; J. -P. Kneib

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arXiv · astro-ph/9908089

Emission-Line Properties of MG2016+112: A Luminous Type-2 Quasar at High Redshift

T. Yamada·S. Yamazaki·M. Hattori·G. Soucail·J. -P. Kneib

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Abstract

We present new high signal-to-noise ratio spectra of the components B and C of the gravitational lensing system MG2016+112. We show that image C displays strong emission lines of Ly$α$, \NV, \CIV, \HeII, and \CIII redshifted to z=3.27, similar to images and B. We examine the emission-line flux ratios in order to put constraints on the lens models as well as to investigate the intrinsic nature of MG2016+112. The observed line ratios of B and C are consistent with those expected in the simple photo-ionization models for narrow-line region of active galactic nuclei (AGN) except for the enhanced \NV\ lines. The line ratios difference of components B and C can be interpreted as a difference in ionization parameters. This result is consistent with lens model prediction that C is a fold image of a slightly outer part of the nucleus. MG2016+112 is known to be very unique among the high-redshift AGN; it is neither an ordinary broad-line quasar nor a powerful radio galaxy as indicated by the width and flux ratio of the emission lines. Together with other observed properties discussed in literature, we argue that MG2016+112 is the highest redshift luminous radio-quiet type-2 quasar.

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T. Yamada, S. Yamazaki, M. Hattori, G. Soucail, J. -P. Kneib. 1999-08-09. Emission-Line Properties of MG2016+112: A Luminous Type-2 Quasar at High Redshift. https://arxiv.org/abs/astro-ph/9908089

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