HST/FOS UV and Optical Observations of the QSO OX 169

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Session 4 -- AGNs
Display presentation, Monday, 9:20-6:30, Pauley Room

[4.16] HST/FOS UV and Optical Observations of the QSO OX 169

A. Diplas, E. A. Beaver, R. D. Cohen, V. T. Junkkarinen, and R. W. Lyons (CASS/UCSD)

We present UV and optical observations of the luminous, low z QSO OX 169 ( z$_{em}$ = 0.21, V = 16.2). HST/FOS data were obtained at a resolution of $\simeq$ 1200, using the high resolution gratings G130H, G190H and G270H. The wavelength coverage of the observations is from $1100$\AA\ to $3300$\AA\ ($908$\AA\ to $2725$\AA\ in the QSO rest frame). Optical spectra obtained with the Lick 3m telescope and CCD spectrograph before and after the HST observations, extend the wavelength coverage to $8756$\AA . The UV spectrum shows strong emission lines for H I Ly$\alpha$ $\lambda$1216, C IV $\lambda$1549, and C III $\lambda$1909. The H I Ly$\alpha$ and C IV lines show absorption at z$_{a}$ $\simeq$ z$_{em}$. The H$\alpha$ and H$\beta$ Balmer lines are double peaked and are known to vary with time. Various models have been suggested in the past in order to explain the origin of the two peaks. Possible explanations include Balmer self absorption from an intervening broad line cloud (Smith, H. E. 1980, ApJ, 241,L137), superposition of broad and narrow line profiles (Gaskell, C. M. 1981, ApJ, 251, 8), and two broad line regions possibly due to a supermassive binary (Stockton, A. \& Farnham, T., ApJ, 371, 525). We compare the new UV and optical observations with the existing models, in order to explain the nature of the absorption.\\

This work is part of Goddard High Resolution Spectrograph Guaranteed Time Observations and is supported by NASA grant No. NAG5-1858.

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