Differencing and Coadding JWST Images with Matched Point Spread Function

Abstract

We present an algorithm to derive difference images for data taken with the JWST with matched point-spread functions (PSFs). It is based on the saccadic fast Fourier transform (SFFT) method but with revisions to accommodate the rotations and spatial variations of the PSFs. It allows for spatially varying kernels in B-spline form with separately controlled photometric scaling and Tikhonov kernel regularization for harnessing the ultimate fitting flexibility. We present this method using the JWST/NIRCam images of galaxy cluster Abell 2744 acquired in JWST Cycle 1 as the test data. The algorithm can be useful for time-domain source detection and differential photometry with the JWST. It can also coadd images of multiple exposures taken at different field orientations. The coadded images preserve the sharpness of the central cores of the PSFs, and the positions and shapes of the objects are matched precisely with B-splines across the field.

20 pages, 7 figures, accepted for publication in AJ, software available at https://github.com/thomasvrussell/sfft

References in corpus (22)

• Array Programming with NumPy
• scikit-image: Image processing in Python
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The Science Performance of JWST as Characterized in Commissioning
• A Long Time Ago in a Galaxy Far, Far Away: A Candidate z ~ 12 Galaxy in Early JWST CEERS Imaging
• The GLASS James Webb Space Telescope Early Release Science Program. I. Survey Design and Release Plans
• CEERS Epoch 1 NIRCam Imaging: Reduction Methods and Simulations Enabling Early JWST Science Results
• A New Algorithm For Difference Image Analysis
• The IPAC Image Subtraction and Discovery Pipeline for the intermediate Palomar Transient Factory
• Photometry and astrometry with JWST -- I. NIRCam Point Spread Functions and the first JWST colour-magnitude diagrams of a globular cluster
• Early results from GLASS-JWST. II: NIRCam extra-galactic imaging and photometric catalog
• Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise Observatory Optical Transient Search (WOOTS)
• A search for transiting planets around FGKM dwarfs and sub-giants in the TESS Full Frame Images of the Southern ecliptic hemisphere
• Shock cooling of a red-supergiant supernova at redshift 3 in lensed images
• The Tsinghua University-Ma Huateng Telescopes for Survey: Overview and Performance of the System
• Astronomical Image Subtraction by Cross-Convolution
• Constraints on Cosmological Parameters with a Sample of Type Ia Supernovae from JWST
• Using 1991T/1999aa-like Type Ia Supernovae as Standardizable Candles
• A First Look at Cepheids in a SN Ia Host with JWST
• Point-like sources among z>11 galaxy candidates: contaminants due to supernovae at high redshifts?
• Retrospective Search for Strongly Lensed Supernovae in the DESI Legacy Imaging Surveys
• Detection of Tidal Disruption Events around Direct Collapse Black Holes at High Redshifts with the James Webb Space Telescope

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