Report
Design, pointing control, and on-sky performance of the mid-infrared vortex coronagraph for the VLT/NEAR experiment
| العنوان: | Design, pointing control, and on-sky performance of the mid-infrared vortex coronagraph for the VLT/NEAR experiment |
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| المؤلفون: | Maire, A. -L., Huby, E., Absil, O., Zins, G., Kasper, M., Delacroix, C., Leveratto, S., Karlsson, M., Ruane, G., Käufl, H. -U., de Xivry, G. Orban, Pathak, P., Pettazzi, L., Duhoux, P., Kolb, J., Pantin, E., Riggs, A. J. Eldorado, Siebenmorgen, R., Mawet, D. |
| المصدر: | J. of Astronomical Telescopes, Instruments, and Systems, 6(3), 035003 (2020) |
| سنة النشر: | 2020 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Instrumentation and Methods for Astrophysics |
| الوصف: | Vortex coronagraphs have been shown to be a promising avenue for high-contrast imaging in the close-in environment of stars at thermal infrared (IR) wavelengths. They are included in the baseline design of METIS. To ensure good performance of these coronagraphs, a precise control of the centering of the star image in real time is needed. We previously developed and validated the quadrant analysis of coronagraphic images for tip-tilt sensing estimator (QACITS) pointing estimator to address this issue. While this approach is not wavelength-dependent in theory, it was never implemented for mid-IR observations, which leads to specific challenges and limitations. Here, we present the design of the mid-IR vortex coronagraph for the new Earths in the $\alpha$ Cen Region (NEAR) experiment with the VLT/VISIR instrument and assess the performance of the QACITS estimator for the centering control of the star image onto the vortex coronagraph. We use simulated data and on-sky data obtained with VLT/VISIR, which was recently upgraded for observations assisted by adaptive optics in the context of the NEAR experiment. We demonstrate that the QACITS-based correction loop is able to control the centering of the star image onto the NEAR vortex coronagraph with a stability down to $0.015 \lambda/D$ rms over 4h in good conditions. These results show that QACITS is a robust approach for precisely controlling in real time the centering of vortex coronagraphs for mid-IR observations. Comment: Published in JATIS. This version is the manuscript resubmitted before acceptance, 30 pages, 14 figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1117/1.JATIS.6.3.035003 |
| URL الوصول: | http://arxiv.org/abs/2012.08190 |
| رقم الانضمام: | edsarx.2012.08190 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1117/1.JATIS.6.3.035003 |
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