2025/03/19 by Euclid Collaboration, G Polenta, Polenta, G. +405 · 1 citation
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Instrumentation and Methods for Astrophysics (astro-ph.IM)
paper · pdf · doi:10.48550/arxiv.2503.15304
openalex publication_date 2025/03/19 · openalex created_date 2025/10/07 · openalex updated_date 2026/07/28
This paper describes the near-infrared processing function (NIR PF) that processes near-infrared images from the Near-Infrared Spectrometer and Photometer (NISP) instrument onboard the Euclid satellite. NIR PF consists of three main components: (i) a common pre-processing stage for both photometric (NIR) and spectroscopic (SIR) data to remove instrumental effects; (ii) astrometric and photometric calibration of NIR data, along with catalogue extraction; and (iii) resampling and stacking. The necessary calibration products are generated using dedicated pipelines that process observations from both the early performance verification (PV) phase in 2023 and the nominal survey operations. After outlining the pipeline's structure and algorithms, we demonstrate its application to Euclid Q1 images. For Q1, we achieve an astrometric accuracy of 9-15 mas, a relative photometric accuracy of 5 mmag, and an absolute flux calibration limited by the 1% uncertainty of the Hubble Space Telescope (HST) CALSPEC database. We characterise the point-spread function (PSF) that we find very stable across the focal plane, and we discuss current limitations of NIR PF that will be improved upon for future data releases.