Faint Field Galaxies around Bright Stars: A New Strategy for Imaging at the Diffraction Limit

Abstract

ABSTRACTThis paper presents a new strategy for observing faint galaxies with high‐order natural guide star systems. We have imaged five high Galactic latitude fields within the isoplanatic patch of bright stars (8.5 mag < R < 10.3 mag). The fields provide a rich set of faint field galaxies that are observable with a natural guide star adaptive optics (AO) system on a large telescope. Because of the small fields of many AO science cameras, these preliminary images are necessary to identify candidate galaxies. We present the photometry and positions for 78 objects (at least 40 galaxies) near five bright stars, appropriate for diffraction‐limited studies with the Keck and other AO systems on large ground‐based telescopes. The K‐band seeing conditions in each field were excellent (0.″4–0.″7), allowing us to identify stars and estimate galaxy sizes. We also simulate AO images of field galaxies to determine the feasibility of infrared morphological studies at the diffraction limit. With new high‐order AO systems coming on line with 8–10 m class telescopes, we believe these observations are invaluable in beginning to study faint galaxy populations at the diffraction limit.