ShaneAO: Predicted performance limits of the new adaptive optics and IR imaging system on the Lick Observatory 3-meter telescope

Srikar Srinath

Date: October 9, 2013

Abstract:

The Lick Observatory's Shane 3-meter telescope is receiving a new infrared camera, adaptive optics system and laser guide star, collectively dubbed ShaneAO. We present the results of modeling the emissivity and throughput of the ShaneAO system in the form of sky backgrounds and limiting magnitudes in the $J$, $H$ and $K$ bands for point sources, constant surface brightness patches and surface brightness profiles. In addition, for spectroscopy we provide minimum exposure times required to overcome detector limits and sky background noise. The model was validated by comparing its results to the Keck telescope adaptive optics system model and then by estimating the sky background and limiting magnitudes for IRCAL, the existing infra-red detector on the Shane telescope, and comparing to measured results. We predict that the ShaneAO system will measure lower sky backgrounds and achieve 20% higher throughput across the $JHK$ bands despite having more optical surfaces than the current system. It will enable imaging and spectroscopy of fainter objects (by 1-2 magnitudes) and will be faster to reach a fiducial signal-to-noise ratio by a factor of 10-13. We also discuss new science that will now be possible with the Shane telescope's enhanced imaging, spectroscopic and polarimetric capabilities.