System analysis and expected performance of a high-contrast module for HARMONI
HARMONI is a first-light visible and near-IR integral field spectrograph of ESO's Extremely Large Telescope (ELT) which will sit on top of Cerro Armazones, Chile. A Single Conjugate Adaptive Optics (SCAO) subsystem will provide diffraction-limited spectro-images in a Nyquist-sampled 0.61 x 0.86 arcsec field of view, with a R=3000-20000 spectral resolution. Inside the instrument, a High Contrast Module (HCM) could give HARMONI the ability to spectrally characterize young giant exoplanets (and disks) with flux ratio down to 10-6 as close as 100-200mas from their star. This would be achieved with an apodized pupil coronagraph to attenuate the diffracted light of the star and limit the dynamic range on the detector, and an internal ZELDA wavefront sensor to calibrate non-common path aberrations, assuming that the surface quality of the relay optics of HARMONI satisfy specific requirements. This communication presents (a) the system analysis that was conducted to converge towards these requirement, and the proposed HCM design, (b) an end-to-end simulation tool that has been built to produce realistic datacubes of hour-long observations, and (c) the estimated performance of the HCM, which has been derived by applying differential imaging techniques on the simulated data.
Ground-based and Airborne Instrumentation for Astronomy VII
- Pub Date:
- July 2018