have complex and highly structured profiles. We discuss, in the context of the discrete cloud model of the broad-line region, three possible mechanisms by which profile structure could be produced: irregularities in the radial luminosity distribution, flattened geometries and ionizing continuum variability. In each case, the structure produced has

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A periodic signal of high nominal significance (99.95 percent) is found in the light curve of OJ 287 in observations taken with the Prime Focus Camera Unit on the 2.5 m Isaac Newton Telescope on two nights in March-April 1987. No such periodicity is seen in the light curve of the simultaneously observed reference star. A null test involving

A periodic signal of high nominal significance (99.95%) is found in the light curve of OJ 287 in observations taken with the Prime Focus Camera Unit on the 2.5 m Isaac Newton Telescope on two nights in March April 1987. No such periodicity is seen in the light curve of the simultaneously observed reference star. A null test involving observations

The results of near-infrared mapping, optical spectroscopy, and millimetric CO J = 2-1 observations of the halo about IC 418 are presented. As a result, it is confirmed that NIR emission extends outside of the principal emission shell, and into a zone characterized by weak optical grain scattering and (in all probability) strong FIR emission. An

Theoretical models are developed to account for the asymmetries observed by Stenflo et al. (1984) in the Stokes V profiles of solar faculae. The approximate dependence of Stokes V on magnetic and velocity fields in the line of sight is characterized under the assumption of local thermodynamic equilibrium, and empirical growth curves for the zero