A team of researchers from the University of California, Los Angeles, the California Institute of Technology, and the W. M. Keck Observatory have proposed a new adaptive optics system designed to enhance the resolution of the Keck I telescope. The researchers, led by Brianna Peck and Jessica R. Lu, have detailed their performance simulations for the Keck Optical Laser Guide Star Adaptive Optics System (KOLA) in a study published in the Journal of Astronomical Telescopes, Instruments, and Systems.
Adaptive optics (AO) systems are crucial for ground-based telescopes as they correct the distortions caused by Earth’s atmosphere, enabling near diffraction-limited angular resolution. The proposed KOLA system aims to achieve high-resolution correction over a wide field of view, specifically targeting a 60 arcsecond area. The system combines multiple laser guide stars (LGS) and deformable mirrors to improve image quality across the observed field.
The researchers used the open-source Multi-Threaded Adaptive Optics Simulator (MAOS) to evaluate KOLA’s performance. They validated the simulator against on-sky data from the current Keck I adaptive optics system. The simulations focused on key metrics such as Strehl ratio, full width at half maximum, and encircled energy radius. These metrics are essential for assessing the system’s ability to resolve fine details in astronomical observations.
The proposed KOLA design includes 10 laser guide stars, 3 tip-tilt natural guide stars (TTNGS), and 3600 actuators on the adaptive secondary mirror. Performance simulations indicate that the system could achieve an angular resolution of 15 milliarcseconds with a Strehl ratio of 34% at 652 nm on-axis. The Strehl ratio is a measure of image quality, with higher values indicating better correction of atmospheric distortions.
The researchers highlight several science-driven requirements for the KOLA system, including resolving black hole spheres of influence, probing crowded stellar fields, and imaging protoplanetary disks. These applications demonstrate the potential of the KOLA system to advance our understanding of various astronomical phenomena.
While the simulations show promising results, the researchers note that further work is needed to optimize the system. This includes exploring alternative configurations of laser guide stars and natural guide stars, optimizing conjugation heights for high-altitude deformable mirrors, and testing performance under poorer seeing conditions. These refinements will be crucial for maximizing the system’s effectiveness in real-world observations.
The study provides a comprehensive overview of the KOLA system’s potential and outlines the steps needed to bring this advanced adaptive optics system to fruition. As ground-based telescopes continue to push the boundaries of astronomical observation, systems like KOLA will play a vital role in enhancing our ability to explore the universe.
This article is based on research available at arXiv.