研究課題/領域番号 |
19J22222
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研究機関 | 東京大学 |
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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キーワード | Weak lensing / Galaxy Shape Measurement / Mass map reconstruction / Hyper Suprime-Cam |
研究実績の概要 |
I ran the FPFS pipeline on the Hyper Suprime-Cam (HSC) first year data release to produce a shear catalog. Several null tests are conducted on the FPFS shape catalog and the results are consistent with those of regaussianization shape catalog. I did not find any potential additive bias from the null test. I compared the galaxy-galaxy lensing measurement produced by the FPFS shape catalog with the measurement of the regaussianization shape catalog. The results from two different shape catalogs are consistent. A mass map has been produced with the FPFS shape catalog and we do not find any E-mode from the mass map. I finished writing the paper for the HSC S16A FPFS shape catalog and submitted it to the Astrophysical Journal.
I learned the sparsity analysis method and use Glimpse, which is a public code, to reconstruct 2-D mass maps using the first year HSC shape catalog. The mass maps are reconstructed with different regularization parameters. I propose to improve the Glimpse algorithms. The first improvement is that I take into the account of the full PDF of the photo-z estimation. The smears along the line-of-sight due to the photo-z uncertainty is included in the bases dictionary. The second advantage is that I use NFW surface density profile to construct the dictionary in the transverse direction. Since NFW well represents the halo shape, the efficiency of halo detection should be improved. The third advantage is the usage of path-wise coordinate descent algorithm to improve the speed of the algorithm.
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現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The full project is divided into three parts: 1) The first part is to develop a robust shear estimator and apply it to Hyper Suprime-Cam data to produce a shear catalog. 2) The second part is to develop a precise 3-D mass map reconstruction algorithm and apply it to the new shear catalog to produce 3-D mass map. 3) The third part is to cross correlate the 3-D mass map with mass map from CMB observations. For the first part of the project, I have finished the development of the FPFS shear estimator, which uses Shapelets of galaxy's Fourier power function to construct shear estimator. Then I calibrate the shear estimator for blending effect using the HSC-like image simulation. Subsequently, I apply the FPFS shear estimator to the first year Hyper Suprime-Cam (HSC) data release. A paper has been submitted to the Astrophysical Journal. For the second part of this project, I have finished the development of new 3-D mass map reconstruction algorithm and are preparing to apply it to HSC data. The new algorithm build up a multi-scale dictionary on NFW halo profile and uses sparsity method for 3D mass map reconstruction. Currently, I am writing a paper on the new mass map reconstruction method. The project goes smoothly as I expected since about a half of the project has been finished.
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今後の研究の推進方策 |
The research plan for the next year is divided into three steps which are layout as follows: First, I will finish writing a paper on the new 3-D mass map reconstruction algorithms and submit the paper before the end of August. The new method builds up a dictionary on NFW halo profile and use sparsity method to reconstruct mass map from galaxy shapes. (From 1st April 2020 to 31th August 2020) Then, I will apply the FPFS shear estimator to the second year Hyper Suprime-Cam (HSC) data release and use the latest image simulation to calibrate the shear estimator and produce a shear catalog based on the second year data release. Then, the shear catalog will be used to make 3-D mass map. A paper on the second year HSC catalog will be submitted before the end of this year. (from 1st September 2020 to 31 December 2020) Finally, I apply the 3-D mass map reconstruction developed from the first step to the shape catalog constructed from the second step to produce a 3-D mass map for the second year HSC data release. (from 1st January 2021 to 31st March 2021)
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