Into the Blue: AO Science with MagAO in the Visible

摘要

We review astronomical results in the visible (λ<1μm) with adaptive optics. Other than a brief period in the early 1990s, there has been little astronomical science done in the visible with Adaptive Optics until recently. The most productive large telescope visible AO system to date is our 6.5m Magellan telescope AO system (MagAO). MagAO is an advanced Adaptive Secondary AO 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 < 9 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 growing power of visible AO to probe circumstellar regions/spatial resolutions that would otherwise require much larger diameter telescopes with classical infrared AO cameras.