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C.Y. Peng (Steward Observatory), L.C. Ho (Carnegie Observatories), A. V. Filippenko (U.C. Berkeley), W.L.W. Sargent (Caltech)
The cores of many nearby galaxies exhibit nuclear activity very similar to that of distant quasars, except at a much lower luminosity. Such low-luminosity active galactic nuclei (LLAGNs) are formidable to study from the ground because the source of the activity dwells within a small region at the core of a galaxy and is intrinsically faint compared with the entire galaxy light output. The high spatial resolution of the Hubble Space Telescope overcomes many difficulties in studying the properties of nearby LLAGNs.
We present preliminary results from a study of 30 Seyfert and 50 LINER galaxies based on WFPC2 images from the HST archive. We discuss the morphology around the active nucleus and quantify the structure of the core by parameterizing it with a ``Nuker'' power law, measuring the luminosity profile and density, isophote shapes, and color when available. Finally, we draw correlations between these parameters and global properties and compare the properties of Type 1 and 2 Seyferts with those of LINERs 1 and 2. We confirm that Type 1 objects in general exhibit more concentrated and compact nuclei than Type 2. In addition, the existence of dust and absorption features down to the smallest resolvable radius around the AGN provides evidence for the standard picture, that obscuration gives rise to some of the observational differences between Type 1 and Type 2 objects.
The author(s) of this abstract have provided an email address for comments about the abstract: cyp@as.arizona.edu