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G. A. Kriss (STScI), Z. Tsvetanov, R. Telfer (JHU)
The geometry of BAL QSOs is highly uncertain. One class of models suggests that the broad absorption line material arises in a wind driven off the accretion disk or obscuring torus surrounding the QSO. An alternative model has the absorption produced by material in a jet directed along our line of sight. In the first case, we view the BAL QSO at high inclination through the wind with our line of sight near the plane of the disk or the torus. In the latter model, the inclination is low, and our line of sight through the jet is near the pole. If the first geometry is correct, narrow-line emission would appear as extended structures lying in the plane of the sky, similar to nearby Seyfert 2 galaxies. If the absorption arises in a jet, then presumably we are viewing the QSO along the axis of symmetry, and any extended emission would either be absent or distributed more symmetrically about the central source as is seen in nearby Seyfert 1s. We have obtained NICMOS images in narrow-band filters of 15 broad absorption line QSOs (BAL QSOs) lying at redshifts of 1.85--2.30 to search for line emission in [O~II] (5 objects), H\beta (1 object), [O~III] (1 object), or H\alpha (8 objects) indicative of extended narrow-line regions. By scaling up the Seyfert 2 galaxy NGC~1068 to a luminosity of 1046~\rm erg~s-1, we would expect to see extended line emission on scales of 3--7 kpc at z=2, or 0.5--1.0 arc second. However, none of the images show any extended structure. All line emission is consistent with either compact narrow-line regions typical of Seyfert 1s, or, in the cases of the H\beta and H\alpha images, with unresolved broad-line region emission.
Support for this work was provided by NASA through grant number GO-07892.02-96A from the STScI, which is operated by AURA, under NASA contract NAS5-26555.
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