2017 Fiscal Year Annual Research Report
Intrinsic alignments in HSC
| Project/Area Number |
17H06599
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Koehlinger Fabian 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (70800556)
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Keywords | intrinsic alignments / consistency / cosmic shear |
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| Outline of Annual Research Achievements |
We set up and started modifying a galaxy-galaxy lensing code to also perform direct measurements of intrinsic galaxy alignments. In the process of this development we realized that for a full pipeline validation we would need a quantitative criterion to establish consistency between different datasets and within a dataset. Therefore, we started to develop a general Bayesian framework to assess the consistency of or within datasets, with a particular focus on weak lensing data sets but in principle also applicable to more general datasets.
Moreover, it turned out that the current overlap of the available first-year HSC shear catalog data with the SDSS MegaZ-LRG sample is insufficient to derive statistically significant direct measurements of intrinsic galaxy alignments. As the shear catalog for the next internal data release of HSC (S18A) has not become available yet either, we started collaborating with the lead-author of the cosmic shear measurement project being performed on the first-year HSC weak lensing catalog. This measurement also yields an indirect measurement of intrinsic galaxy alignments (to be marginalized over as a nuisance). Therefore, we finalized our likelihood analysis pipeline and made it available to this project to derive at least an indirect measurement of intrinsic galaxy alignments in the first-year HSC weak lensing data.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
The development of the Bayesian consistency assessment framework was an unforeseen but necessary development which is on track to lead to a peer-reviewed publication in FY2018 though.
Moreover, we needed to re-adjust the goal of a direct measurement of intrinsic galaxy alignments to an indirect measurement through participation in a cosmic shear measurement project.
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| Strategy for Future Research Activity |
We will finalize the Bayesian consistency assessment framework and bring it to publication within FY2018.
Also the indirect measurement of intrinsic galaxy alignments through a cosmic shear measurement is on track to yield a co-authored publication in FY2018.
If the new shear catalog based on the S18A internal data release of HSC becomes available in FY2018 we will carry out also the direct measurement of the intrinsic galaxy alignments with the tools and frameworks developed within this project up to now.
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Research Products
(2 results)
