An analysis of the narrow-line profiles in high ionization Seyfert galaxies

Abstract

Narrow optical emission-line profiles representing a wide range in ionization potential for 12 high-ionization Seyfert galaxies are analyzed using deconvolution techniques. The data reduction process is described in detail. A good correlation is found between line width and ionization potential in many of the objects. For some galaxies a good correlation is also found between line width and critical density. For a given object, the ratios of line widths at various fractions of full intensity are remarkably similar over the entire range of ionization potential and critical density. Almost identical velocity ratios at corresponding fractions of maximum intensity are found for profiles from an individual line (e.g., [Fe vu] ^6087) taken from every object. In particular the relation between the velocity widths at \ and £ maximum intensity is the same found for the widths of the broad profiles of Hß in Seyfert 1 galaxies and QSOs by De Robertis (1984a). This may suggest that a similar acceleration mechanism (and/or geometry) operates in all objects in both the broad-and narrow-line regions. The high-ionization line widths correlate only poorly with the absolute blue magnitude of the galaxy, while the lower ionization lines show a good correlation. On average, half of the galaxies have narrow line profiles which are skewed to the blue, half which are symmetric. The low-ionization lines display little asymmetry in general, while the high-ionization lines tend to have blueward excesses. The possible implication of these and other correlations, and the absence of still other correlations, are discussed. Descriptions of the details of the individual spectra are presented. Subject headings: galaxies: Seyfert-line profiles 171

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