Year: 2025
Type: article
Abstract: The existing large-scale weak lensing surveys typically reserve the best seeing conditions for a certain optical band to minimize shape measurement errors and maximize the number of usable background galaxies. This is because most popular shear measurement methods contain explicit or implicit thresholds on the galaxy-to-point-spread-function size ratio, below which their shape measurement errors increase abruptly. Using the Dark Energy Camera Legacy Survey data, we have previously demonstrated that the Fourier_Quad method performs very well on poorly resolved galaxy images in general. It is therefore a ready tool for shear measurement with multiband images regardless of their seeing conditions. In this paper, we apply the Fourier_Quad pipeline on the multiband images from the third public data release of the Hyper Suprime-Cam Subaru Strategic Program. We estimate the shear measurement bias using the field distortion test. The results show that the multiplicative biases of g 1 in all five bands ( g / r / i / z / y ) and g 2 in the g / i / y bands are consistent with zero within ∼2 σ . Only the g 2 results in r , z bands show somewhat significant biases ( 1 0 2 m 2 r , z = 2.18 ± 0.69, 3.46 ± 0.62 respectively). As for the additive biases, most of them are different from zero by more than 3 σ ( 1 0 4 c 1 g , r , i , z , y = 1.0 ± 1.0, −3.3 ± 0.9, −5.8 ± 0.7, −4.6 ± 0.6, −27.0 ± 0.8; 1 0 4 c 2 g , r , i , z , y =−3.5 ± 0.8, −2.2 ± 0.6, −2.3 ± 0.4, −0.0 ± 0.5, 1.0 ± 0.9). Using the LOWZ and CMASS galaxies as foreground lenses, we show that the error bar in the galaxy–galaxy lensing measurement can be decreased by factors of around 15% by combining shear catalogs from different bands. This indicates that it is worth taking multiband shear measurements for better shear statistics.
Source: The Astrophysical Journal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: Princeton University, Ministry of Education, Culture, Sports, Science and Technology, National Natural Science Foundation of China, Academia Sinica, Cabinet Office, Government of Japan, National Astronomical Observatory of Japan, High Energy Accelerator Research Organization, Toray Science Foundation, Japan Society for the Promotion of Science, Japan Science and Technology Agency
OpenAlex ID: W4415781398