A differentiable perturbation-based weak lensing shear estimator

Journal Article · Mon Dec 18 00:00:00 EST 2023 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stad3895· OSTI ID:2483476

Li, Xiangchong ^[1]; Mandelbaum, Rachel ^[2]; Jarvis, Mike ^[3]; Li, Yin ^[4]; Park, Andy ^[2]; Zhang, Tianqing ^[2]

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1. Carnegie Mellon University, Pittsburgh, PA (United States); University of Tokyo, Chiba (Japan); Carnegie Mellon University, Pittsburgh, PA 15213
2. Carnegie Mellon University, Pittsburgh, PA (United States)
3. University of Pennsylvania, Philadelphia, PA (United States)
4. Peng Cheng Laboratory, Guangdong (China)

Upcoming imaging surveys will use weak gravitational lensing to study the large-scale structure of the Universe, demanding sub-per cent accuracy for precise cosmic shear measurements. We present a new differentiable implementation of our perturbation-based shear estimator (fpfs), using jax, which is publicly available as part of a new suite of analytic shear algorithms called anacal. This code can analytically calibrate the shear response of any non-linear observable constructed with the fpfs shapelets and detection modes utilizing autodifferentiation (ad), generalizing the formalism to include a family of shear estimators with corrections for detection and selection biases. Using the ad capability of jax, it calculates the full Hessian matrix of the non-linear observables, which improves the previously presented second-order noise bias correction in the shear estimation. As an illustration of the power of the new anacal framework, we optimize the effective galaxy number density in the space of the generalized shear estimators using an LSST-like galaxy image simulation for the 10 yr LSST. For the generic shear estimator, the magnitude of the multiplicative bias |m| is below 3 × 10^–3 (99.7 per cent confidence interval), and the effective galaxy number density is improved by 5 per cent. We also discuss some planned future additions to the anacal software suite to extend its applicability beyond the fpfs measurements.

• Research Organization: Carnegie Mellon University, Pittsburgh, PA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0010118
• OSTI ID: 2483476
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 527; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS
cosmology: observations
gravitational lensing: weak
techniques: image processing