Near-IR Weak-Lensing (NIRWL) Measurements in the CANDELS Fields I: Point-Spread Function Modeling and Systematics
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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866914741015805952 |
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| author | Finner, Kyle Lee, Bomee Chary, Ranga-Ram Jee, M. James Hirata, Christopher Congedo, Giuseppe Taylor, Peter Hyeonghan, Kim |
| author_facet | Finner, Kyle Lee, Bomee Chary, Ranga-Ram Jee, M. James Hirata, Christopher Congedo, Giuseppe Taylor, Peter Hyeonghan, Kim |
| contents | We have undertaken a Near-IR Weak Lensing (NIRWL) analysis of the wide-field CANDELS HST/WFC3-IR F160W observations. With the Gaia proper-motion-corrected catalog as an astrometric reference, we updated the astrometry of the five CANDELS mosaics and achieved an absolute alignment within $0.02\pm0.02$ arcsec on average, which is a factor of several superior to existing mosaics. These mosaics are available to download. We investigated the systematic effects that need to be corrected for weak-lensing measurements. We find the largest contributing systematic effect is caused by undersampling. Using stars as a probe of the point-spread function (PSF), we find a sub-pixel centroid dependence on the PSF shape that induces a change in the PSF ellipticity and size by up to 0.02 and $3\%$, respectively. We find that the brighter-fatter effect causes a $2\%$ increase in the size of the PSF and discover a brighter-rounder effect that changes the ellipticity by 0.006. Based on the narrow bandpasses of the WFC3-IR filters and the small range of slopes in a galaxy's spectral energy distribution (SED) within the bandpasses, we suggest that the impact of galaxy SED on PSF is minor in the NIR. Finally, we modeled the PSF of WFC3-IR F160W for weak lensing using a principal component analysis. The PSF models account for temporal and spatial variations of the PSF. The PSF corrections result in residual ellipticities and sizes, $|de_1| < 0.0005\pm0.0003$, $|de_2| < 0.0005\pm0.0003$, and $|dR| < 0.0005\pm0.0001$, that are sufficient for the upcoming NIRWL search for massive overdensities in the five CANDELS fields. NIRWL Mosaics: https://archive.stsci.edu/hlsp/candelsnirwl |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2301_07725 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Near-IR Weak-Lensing (NIRWL) Measurements in the CANDELS Fields I: Point-Spread Function Modeling and Systematics Finner, Kyle Lee, Bomee Chary, Ranga-Ram Jee, M. James Hirata, Christopher Congedo, Giuseppe Taylor, Peter Hyeonghan, Kim Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics We have undertaken a Near-IR Weak Lensing (NIRWL) analysis of the wide-field CANDELS HST/WFC3-IR F160W observations. With the Gaia proper-motion-corrected catalog as an astrometric reference, we updated the astrometry of the five CANDELS mosaics and achieved an absolute alignment within $0.02\pm0.02$ arcsec on average, which is a factor of several superior to existing mosaics. These mosaics are available to download. We investigated the systematic effects that need to be corrected for weak-lensing measurements. We find the largest contributing systematic effect is caused by undersampling. Using stars as a probe of the point-spread function (PSF), we find a sub-pixel centroid dependence on the PSF shape that induces a change in the PSF ellipticity and size by up to 0.02 and $3\%$, respectively. We find that the brighter-fatter effect causes a $2\%$ increase in the size of the PSF and discover a brighter-rounder effect that changes the ellipticity by 0.006. Based on the narrow bandpasses of the WFC3-IR filters and the small range of slopes in a galaxy's spectral energy distribution (SED) within the bandpasses, we suggest that the impact of galaxy SED on PSF is minor in the NIR. Finally, we modeled the PSF of WFC3-IR F160W for weak lensing using a principal component analysis. The PSF models account for temporal and spatial variations of the PSF. The PSF corrections result in residual ellipticities and sizes, $|de_1| < 0.0005\pm0.0003$, $|de_2| < 0.0005\pm0.0003$, and $|dR| < 0.0005\pm0.0001$, that are sufficient for the upcoming NIRWL search for massive overdensities in the five CANDELS fields. NIRWL Mosaics: https://archive.stsci.edu/hlsp/candelsnirwl |
| title | Near-IR Weak-Lensing (NIRWL) Measurements in the CANDELS Fields I: Point-Spread Function Modeling and Systematics |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2301.07725 |