Copyright 2016 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
All documents in ORBi are protected by a user license.
[en] Small inner working angle coronagraphs are essential to benefit from the full potential of large and future extremely large ground-based telescopes, especially in the context of the detection and characterization of exoplanets. Among existing solutions, the vortex coronagraph stands as one of the most effective and promising solutions. However, for focal-plane coronagraph, a small inner working angle comes necessarily at the cost of a high sensitivity to pointing errors. This is the reason why a pointing control system is imperative to stabilize the star on the vortex center against pointing drifts due to mechanical flexures, that generally occur during observation due for instance to temperature and/or gravity variations. We have therefore developed a technique called QACITS[SUP]1[/SUP] (Quadrant Analysis of Coronagraphic Images for Tip-tilt Sensing), which is based on the analysis of the coronagraphic image shape to infer the amount of pointing error. It has been shown that the flux gradient in the image is directly related to the amount of tip-tilt affecting the beam. The main advantage of this technique is that it does not require any additional setup and can thus be easily implemented on all current facilities equipped with a vortex phase mask. In this paper, we focus on the implementation of the QACITS sensor at Keck/NIRC2, where an L-band AGPM has been recently commissioned (June and October 2015), successfully validating the QACITS estimator in the case of a centrally obstructed pupil. The algorithm has been designed to be easily handled by any user observing in vortex mode, which is available for science in shared risk mode since 2016B.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Huby, Elsa ; Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Absil, Olivier ; Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Mawet, Dimitri; California Institute of Technology (United States)
Huby, E., Baudoz, P., Mawet, D., and Absil, O., "Post-coronagraphic tip-Tilt sensing for vortex phase masks: The QACITS technique, " A&A 584, A74 (Dec. 2015).
Mawet, D., Serabyn, E., Liewer, K., Burruss, R., Hickey, J., and Shemo, D., "The Vector Vortex Corona-graph: Laboratory Results and First Light at Palomar Observatory, " ApJ 709, 53-57 (Jan. 2010).
Delacroix, C., Absil, O., Mawet, D., Hanot, C., Karlsson, M., Forsberg, P., Pantin, E., Surdej, J., and Habraken, S., "A diamond AGPM coronagraph for VISIR, " Proc. SPIE 8446, 8 (Sept. 2012).
Kerber, F., Kau, H.-U., Baksai, P., Di Lieto, N., Dobrzycka, D., Duhoux, P., Finger, G., Heikamp, S., Ives, D., Jakob, G., Lundin, L., Mawet, D., Mehrgan, L., Momany, Y., Moreau, V., Pantin, E., Riquelme, M., Sandrock, S., Siebenmorgen, R., Smette, A., Taylor, J., van den Ancker, M., Valdes, G., Venema, L., and Weilenmann, U., "VISIR upgrade overview and status, " Proc. SPIE 9147, 0 (July 2014).
Mawet, D., Absil, O., Delacroix, C., Girard, J. H., Milli, J., O'Neal, J., Baudoz, P., Boccaletti, A., Bourget, P., Christiaens, V., Forsberg, P., Gonte, F., Habraken, S., Hanot, C., Karlsson, M., Kasper, M., Lizon, J.-L., Muzic, K., Olivier, R., Pe~na, E., Slusarenko, N., Tacconi-Garman, L. E., and Surdej, J., "L'-band AGPM vector vortex coronagraph's first light on VLT/NACO. Discovery of a late-Type companion at two beamwidths from an F0V star, " A&A 552, L13 (Apr. 2013).
Defrffere, D., Absil, O., Hinz, P., Kuhn, J., Mawet, D., Mennesson, B., Skemer, A., Wallace, K., Bailey, V., Downey, E., Delacroix, C., Durney, O., Forsberg, P., Gomez, C., Habraken, S., Hoffmann, W. F., Karlsson, M., Kenworthy, M., Leisenring, J., Montoya, M., Pueyo, L., Skrutskie, M., and Surdej, J., "L'-band AGPM vector vortex coronagraph's first light on LBTI/LMIRCam, " Proc. SPIE 9148, 3 (July 2014).
Femena Castella, B., Serabyn, E., Mawet, D., Absil, O., Wizinowich, P., Matthews, K., Huby, E., Bottom, M., Campbell, R., Chan, D., Carlomagno, B., Cetre, S., Defrere, D., Delacroix, C., Gomez Gonzalez, C., Jolivet, A., Karlsson, M., Lanclos, K., Lilley, S., Milner, S., Ngo, H., Reggiani, M., Simmons, J., Tran, H., Vargas Catalan, E., and Wertz, O., "Commissioning and first light results of an L-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument, " Proc. SPIE (2016).
Mawet, D., Riaud, P., Absil, O., and Surdej, J., "Annular Groove Phase Mask Coronagraph, " ApJ 633, 1191-1200 (Nov. 2005).
Forsberg, P., Vargas, E., Delacroix, C., Absil, O., Carlomagno, B., Mawet, D., Habraken, S., Surdej, J., and Karlsson, M., "Realizing the diamond annular groove phase masks for the mid infrared region: five years of successful process development of diamond plasma etching, " Proc. SPIE 9151, 915119 (July 2014).
Absil, O., Mawet, D., Karlsson, M., Defrffere, D., Delacroix, C., Femenia, B., Girard, J., , Hinz, P., Huby, E., Matthews, K., Pantin, E., Serabyn, E., Tristram, K. R. W., Wizinowich, P., Carlomagno, B., Christiaens, V., Forsberg, P., Gomez Gonzalez, C., Habraken, S., Jolivet, A., Milli, J., Piron, P., Reggiani, M., Surdej, J., Vargas Catalan, E., and Wertz, O., "Three years of harvest with the vector vortex coronagraph in the thermal infrared, " Proc. SPIE (2016).
Mawet, D., Pueyo, L., Lawson, P., Mugnier, L., Traub, W., Boccaletti, A., Trauger, J. T., Gladysz, S., Serabyn, E., Milli, J., Belikov, R., Kasper, M., Baudoz, P., Macintosh, B., Marois, C., Oppenheimer, B., Barrett, H., Beuzit, J.-L., Devaney, N., Girard, J., Guyon, O., Krist, J., Mennesson, B., Mouillet, D., Murakami, N., Poyneer, L., Savransky, D., Vfferinaud, C., and Wallace, J. K., "Review of small-Angle coronagraphic techniques in the wake of ground-based second-generation adaptive optics systems, " Proc. SPIE 8442, 4 (Sept. 2012).
Mas, M., Baudoz, P., Rousset, G., and Galicher, R., "Tip-Tilt estimation and correction using FQPM coronagraphic images, " A&A 539, A126 (Mar. 2012).
