Document Type
Article
Publication Date
1-1-2020
Publication Title
Journal of Astronomical Telescopes, Instruments, and Systems
Abstract
We present a revision to the astrometric calibration of the Gemini Planet Imager (GPI), an instrument designed to achieve the high contrast at small angular separations necessary to image substellar and planetary-mass companions around nearby, young stars. We identified several issues with the GPI data reduction pipeline (DRP) that significantly affected the determination of the angle of north in reduced GPI images. As well as introducing a small error in position angle measurements for targets observed at small zenith distances, this error led to a significant error in the previous astrometric calibration that has affected all subsequent astrometric measurements. We present a detailed description of these issues and how they were corrected. We reduced GPI observations of calibration binaries taken periodically since the instrument was commissioned in 2014 using an updated version of the DRP. These measurements were compared to observations obtained with the NIRC2 instrument on Keck II, an instrument with an excellent astrometric calibration, allowing us to derive an updated plate scale and north offset angle for GPI. This revised astrometric calibration should be used to calibrate all measurements obtained with GPI for the purposes of precision astrometry.
Keywords
astrometric calibration, data processing, Gemini Planet Imager, high-contrast imaging
Volume
6
Issue
1
DOI
10.1117/1.JATIS.6.1.015006
ISSN
23294124
Recommended Citation
De Rosa, Robert J.; Nguyen, Meiji M.; Chilcote, Jeffrey; MacIntosh, Bruce; Perrin, Marshall D.; Konopacky, Quinn; Wang, Jason J.; Duchêne, Gaspard; Nielsen, Eric L.; Rameau, Julien; Ammons, S. Mark; Bailey, Vanessa P.; Barman, Travis; Bulger, Joanna; Cotten, Tara; Doyon, Rene; Esposito, Thomas M.; Fitzgerald, Michael P.; Follette, Katherine B.; Gerard, Benjamin L.; Goodsell, Stephen J.; Graham, James R.; Greenbaum, Alexandra Z.; Hibon, Pascale; Hung, Li Wei; Ingraham, Patrick; Kalas, Paul; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marley, Mark S.; Marois, Christian; Ward-Duong, Kimberly; and al, et, "Revised Astrometric Calibration of the Gemini Planet Imager" (2020). Astronomy: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/ast_facpubs/114
Comments
Archived as published.