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A Very Extended Ionized Nebula around the Quasar MR2251-178

P. L. Shopbell, S. Veilleux
Department of Astronomy, Univ. of Maryland, College Park, MD 20742,

J. Bland-Hawthorn
Anglo-Australian Observatory, P.O. Box 296, Epping, NSW 2121


We report the results of deep emission-line (H$\alpha $) imaging of the ionized gas surrounding the low-redshift ($z=0.0638$) quasar MR 2251-178 using the Taurus Tunable Filter on the AAT telescope. Our observations detect ionized gas out to a radius of 120 kpc, the deepest detection yet in this system. The total mass of ionized gas is $6\times10^{10}$ M$_{\sun}$ (upper limit). The large and symmetric extent of the gaseous envelope favors a model in which the filamentary and diffuse emission arises from a large cloud complex, photo-excited by the bright quasar. A crude kinematic analysis does not support an origin for the gas in an interaction with the nearby galaxy G1. We conclude that significant quantities of ionized gas in the galactic environment may go undetected with current observational techniques.

Patrick Shopbell 2000-11-28