| 研究課題/領域番号 |
19J22222
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 補助金 |
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| 応募区分 | 国内 |
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| 審査区分 |
小区分15020:素粒子、原子核、宇宙線および宇宙物理に関連する実験
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| 研究機関 | 東京大学 |
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研究代表者 |
LI Xiangchong 東京大学, 理学系研究科, 特別研究員(DC1)
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| 研究期間 (年度) |
2019-04-25 – 2022-03-31
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| 研究課題ステータス |
完了 (2021年度)
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| 配分額 *注記 |
2,500千円 (直接経費: 2,500千円)
2021年度: 800千円 (直接経費: 800千円)
2020年度: 800千円 (直接経費: 800千円)
2019年度: 900千円 (直接経費: 900千円)
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| キーワード | gravitational lensing / cosmology observations / image processing / galaxy clusters / observational cosmology / Weak lensing / Galaxy Shape Measurement / Mass map reconstruction / Hyper Suprime-Cam |
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| 研究開始時の研究の概要 |
Firstly, I will provide a FPFS shape catalog on the S18A data release of the Hyper Suprime-Cam Subaru Strategic (HSC-SSP) Survey. I will improve the accuracy of FPFS shear estimator by studying the Shapelet modes of noise Fourier power function.
Then, I will compare the performance of different 2-D mass reconstruction methods on the mock shape catalogs of the HSC-SSP survey on the S18A Survey region.
Finally I will finish 3-D mass map re-construction using sparsity analysis with the shape catalogs of the S18A data release of the HSC-SSP Program.
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| 研究実績の概要 |
I analytically developed an improved version of the Fourier Power Function Shapelets (FPFS) algorithm for accurate and fast shear estimation. The method now includes analytic corrections for sources of bias that plague all shape measurement algorithms: including noise bias (due to noise in nonlinear combinations of observable quantities) and selection bias (due to sheared galaxies being more or less likely to be detected). Crucially, these analytic solutions do not rely on calibration from external image simulations. For isolated galaxies, the small residual less than 0.001 multiplicative bias and less than 0.0001 additive bias now meet science requirements for Stage IV experiments. FPFS also works accurately for faint galaxies and robustly against stellar contamination.
I conducted several systematic null tests for the HSC three-year cosmic shear measurement. One is to test the systematics in cosmic shear measurement caused by model residuals of point spread function due to diffraction of telescope and atmosphere. I cross-correlate galaxy shape with star shape to detect the PSF modelling residual in the galaxy shapes. The other null test is to check the B-mode systematics in the weak-lensing science. Then I looked into the influence of baryonic effect, the influence of the intrinsic alignment in the cosmic shear measurement. I have built up the analysis pipeline for HSC three year weak lensing cosmological constraints.
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| 現在までの達成度 (段落) |
令和3年度が最終年度であるため、記入しない。
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| 今後の研究の推進方策 |
令和3年度が最終年度であるため、記入しない。
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