| 研究実績の概要 |
After developing the HBT+ code for subhalo finding, in FY2018 we have applied the code to simulations to study the properties and distributions of halos and subhalos, as well as carrying out some observational studies of matter distribution around halos.On large scale, we carried out a multi-dimensional analysis of the clustering of central subhalos, to shed light on the origin of their assembly bias. For the first time, we are able to explicitly show that the dependences of bias on halo mass, concentration (or formation history), spin and shape are non-redundant with respect to each other, indicating their different physical origins. We also find that an environmental density is able to largely account for all the bias dependences. This reveals a new way to understand and model the large scale clustering of halos and subhalos. We have further used the subhalo catalog to develop a new algorithm for correcting for the fibre-collision effect in observational measurements of galaxy/halo clustering, and to study the lensing signal around low density regions in different cosmological models.On small scales, starting from simulated mergers of galaxies and subhalos, we developed a new code (StarGO) to identify substructures in the stellar halo around galaxies using a technique called self-organizing map. It can be applied to real observations such as the GAIA survey to study the small scale matter distribution and potentially constrain the property of dark matter. We have also used real observational data from HSC to study the stacked stellar halo around isolated galaxies.
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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 plan in FY2018 was to study the distribution and properties of dark matter halos and subhalos identified with our new code. We have studied the properties and clustering of halos and subhalos on both large and small scale, in both simulations and observations, covering both the dark matter and stellar components, and also extended to different cosmological models.
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