Improving the astrometric solution of the Hyper Suprime-Cam with anisotropic Gaussian processes

Journal Article · 08 June 2021 · Astronomy and Astrophysics

DOI: https://doi.org/10.1051/0004-6361/202140463 · OSTI ID:1807687

Léget, P. -F. ^[1]; Astier, P. ^[2]; Regnault, N. ^[2]; Jarvis, M. ^[3]; Antilogus, P. ^[2]; Roodman, A. ^[4]; Rubin, D. ^[5]; Saunders, C. ^[6]

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1. LPNHE, CNRS/IN2P3, Sorbonne Univ., Paris (France). Laboratoire de Physique Nucléaire et de Hautes Énergies; Stanford Univ., CA (United States). Kavli Institute for Particle Astrophysics & Cosmology
2. LPNHE, CNRS/IN2P3, Sorbonne Univ., Paris (France). Laboratoire de Physique Nucléaire et de Hautes Énergies
3. Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Physics and Astronomy
4. Stanford Univ., CA (United States). Kavli Institute for Particle Astrophysics & Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States)
5. Univ. of Hawaii at Manoa, Honolulu, HI (United States). Dept. of Physics and Astronomy; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
6. Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences; LPNHE, CNRS/IN2P3, Sorbonne Univ., Paris (France). Laboratoire de Physique Nucléaire et de Hautes Énergies

Context. We study astrometric residuals from a simultaneous fit of Hyper Suprime-Cam images. Aims. We aim to characterize these residuals and study the extent to which they are dominated by atmospheric contributions for bright sources. Methods. We used Gaussian process interpolation with a correlation function (kernel) measured from the data to smooth and correct the observed astrometric residual field. Results. We find that a Gaussian process interpolation with a von Kármán kernel allows us to reduce the covariances of astrometric residuals for nearby sources by about one order of magnitude, from 30 mas² to 3 mas² at angular scales of ~1 arcmin. This also allows us to halve the rms residuals. Those reductions using Gaussian process interpolation are similar to recent result published with the Dark Energy Survey dataset. We are then able to detect the small static astrometric residuals due to the Hyper Suprime-Cam sensors effects. We discuss how the Gaussian process interpolation of astrometric residuals impacts galaxy shape measurements, particularly in the context of cosmic shear analyses at the Rubin Observatory Legacy Survey of Space and Time.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1807687
• Journal Information: Astronomy and Astrophysics, Journal Name: Astronomy and Astrophysics Vol. 650; ISSN 0004-6361
• Publisher: EDP SciencesCopyright Statement
• Country of Publication: United States
• Language: English