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Session 43 - Source Surveys.
Display session, Wednesday, June 11
South Main Hall,
We present results derived from a recent Hubble Space Telescope imaging survey of the Ultraluminous IR Galaxies. The most significant issue related to this sample of galaxies has been identifying the nature of the primary energy source: starburst or AGN? Through a high-resolution imaging survey of a large sample, some properties of this class of objects are now being better defined, which is helping to clarify the nature of the energy source. Fine structure is seen within the central arcsecond of each galaxy in the sample. In some cases, the structure is smooth and centrally concentrated, suggestive of a bright nuclear energy source (AGN?). In many other cases, the sub-arcsecond morphology is chaotic and extended, suggestive of strong starburst activity. The peculiar, disturbed morphologies that are seen on large (kiloparsec) scales among this sample of galaxies are continued down to the smallest scales in the cores of these strongly starbursting systems. A variety of morphological features are noted, many of which are related to the recent intense interaction-induced star formation episode. These starburst-related features (e.g., numerous bright clumps of star formation, shells, and bubbles) are similar to those seen in previous HST imaging observations of the Cartwheel Ring Galaxy, the Antennae (NGC 4038/4039), NGC 7252, and other strongly interacting and merging galaxies.
Program listing for Wednesday