Zusammenfassung
We review astronomical results in the visible (łambda<1\mum) with
adaptive optics. Other than a brief period in the early 1990s, there has been
little astronomical science done in the visible with AO until recently. The
most productive visible AO system to date is our 6.5m Magellan telescope AO
system (MagAO). MagAO is an advanced Adaptive Secondary system at the Magellan
6.5m in Chile. This secondary has 585 actuators with < 1 msec response times
(0.7 ms typically). We use a pyramid wavefront sensor. The relatively small
actuator pitch (~23 cm/subap) allows moderate Strehls to be obtained in the
visible (0.63-1.05 microns). We use a CCD AO science camera called "VisAO".
On-sky long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62
microns (r') with the VisAO camera in 0.5" seeing with bright R < 8 mag stars.
These relatively high visible wavelength Strehls are made possible by our
powerful combination of a next generation ASM and a Pyramid WFS with 378
controlled modes and 1000 Hz loop frequency. We'll review the key steps to
having good performance in the visible and review the exciting new AO visible
science opportunities and refereed publications in both broad-band (r,i,z,Y)
and at Halpha for exoplanets, protoplanetary disks, young stars, and emission
line jets. These examples highlight the power of visible AO to probe
circumstellar regions/spatial resolutions that would otherwise require much
larger diameter telescopes with classical infrared AO cameras.
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