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Summary and Future Directions

Our deep H $\alpha$ observations of MR 2251-178 reveal a spiral complex of ionized material that extends more or less symmetrically out to $\sim$ 120 kpc from the quasar. The coarse velocity field derived from our data shows a NE - SW velocity gradient that is opposite to that of the inner line-emitting region. The morphology and kinematics of the nebula cannot be easily explained by an interaction/merger event or a cooling flow. We favor the scenario in which the ionized material is part of a larger neutral envelope that is photoionized by the radiation field of the quasar. Deep HI 21-cm observations are needed to confirm this model.

We suspect that significant quantities of ionized gas may be present around luminous quasars, but have remained undetected with standard narrowband imaging techniques. The observations presented herein constitute only 40 minutes of integration, yet reach more than an order of magnitude deeper in flux than previous narrowband imagery. The TTF instrument allows the observer to tune the filter to a very precise bandpass in order to match the expected emission and avoid bright sky features. The TTF therefore promises to greatly impact a number of observational programs, such as those that aim at parameterizing ionized quasar envelopes and quantifying the impact of quasars on the intergalactic environment.

Acknowledgments:

SV is grateful for support of this research by NSF/CAREER grant AST-9874973 and by a Cottrell Scholarship awarded by the Research Corporation.

Patrick Shopbell
1999-08-26