2017 Fiscal Year Research-status Report
Stronger together: Joint probes for the measurement of the neutrino mass using the Hyper Suprime-Cam survey
| Project/Area Number |
17K14274
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Kwan Juliana 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (20793566)
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Keywords | cosmology / large scale structure |
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| Outline of Annual Research Achievements |
One of the main goals of this project is to develop an analysis pipeline that could look for the effects of massive neutrinos in cosmological observables such as weak lensing and galaxy clustering. In particular, I proposed to develop a fast prediction scheme based on Gaussian Process regression, called emulators, to make theoretical predictions for these observational quantities based on the halo bias and halo mass function.
1.1. Analysis of N-body simulations. Using N-body simulations of large scale structure that included the effects of massive neutrinos and dynamical dark energy, I made precise measurements of the halo bias and halo mass function. I was able to determine how the non-linear halo bias is affected by massive neutrino cosmologies.
1.2. Development of Prediction Tools. I constructed an emulator using the N-body measurements of the halo bias and halo mass function. The construction of the emulators has been completed and I verified that its accuracy is appropriate for our stated plan of analyzing images from the Hyper Suprime-Cam Survey. The emulators have been incorporated into a pipeline for likelihood analysis of cosmic shear, galaxy-galaxy lensing and galaxy clustering measurements.
1.3. Growth of Structure. I have begun making measurements of the redshift space 2-point statistics in the same simulations to construct an emulator for these quantities also.
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| Current Status of Research Progress |
Current Status of Research Progress
4: Progress in research has been delayed.
Reason
The current status of the project has been delayed with respect to the initial project proposal. The shear catalogues from the HSC survey were finalized later than expected and as such the measurements of the cosmic shear and galaxy-galaxy lensing are still undergoing testing for systematics. We also discovered some additional complications with the simulations that required some of the analysis to be redone. In some ways, the delay on the weak lensing measurements means that other aspects of the project has been ahead of schedule. For instance, the development of growth of structure tools is already underway, although that was forecasted to begin in FY2018.
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| Strategy for Future Research Activity |
Because of the delay in the shear catalogues, I will proceed with my backup plan and use currently available measurements as outlined in my proposal and update my work with the newer measurements when they are finalized.
I also intend to add the effect of redshift space distortions to enable the growth rate of large scale structure to be constrained and increase the number of probes that can be used to measure the neutrino mass. This is already underway.
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| Causes of Carryover |
Two publication charges from FY2017, one on the halo bias and one on constraints on neutrino mass, (delayed because of the measurements).
The two publications expected to be carried over plus an additional publication from the growth rate constraints (about 370k in total). I also intend to go on three business trips - one to a collaborator at UC Santa Cruz to discuss our work on redshift space distortions and the neutrino mass and other to Argonne National Laboratory to discuss the N-body simulations. I also anticipate traveling to a workshop or conference to present the results. The total amount will be 1000k.
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