AAS 207th Meeting, 8-12 January 2006
Session 78 Seeing the Universe in a New (Sodium) Light: Early Science Results from Laser Guide Star Adaptive Optics
Poster, Tuesday, 9:20am-6:30pm, January 10, 2006, Exhibit Hall

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[78.08] Laser Guide Star Observations of Super Star Clusters in NGC 1569 and AO PSF Estimation in Crowded Fields

C. D. Sheehy, N. McCrady, J. R. Graham (UC Berkeley)

We have used the Keck LGS AO system to image the field of super star clusters A and B in the dwarf starburst galaxy NGC 1569. The observations were obtained in good conditions and the Strehl ratio at H band is ~15%. With this modest Strehl correction, the qualitative impression is that the LGS/AO images are significantly less confused than the HST/NIC2 observations of this field.

We have used a linear systems approach to describe the imaging performance of the atmosphere, AO system and science camera, and develop a semi-emiprical model of the PSF by fitting for the optical transfer function in the Fourier domain. Experiments with simulated data confirm the utility of this approach for crowded fields in cases where traditional algorithms, e.g., STARFINDER, fail. We confirm the integrity of the LGS AO photometry extracted using these PSFs by comparing the Keck data with HST NICMOS F160W data.

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Bulletin of the American Astronomical Society, 37 #4
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