| 研究実績の概要 |
In FY2019 we have further extended our model to study the dynamical distribution of satellite subhalos and satellite galaxies, and developed a new method to infer the dark matter halo mass profile from satellite dynamics.
The halo mass of the Milky Way is a fundamental quantity that is crucial for the cosmological interpretation of many near field observations. Our previous work have demonstrated the large uncertainty associated with this quantity in the literature. We have also shown there is an intrinsic uncertainty in the inferred dynamical mass arising from the deviations from steady-state of a dark matter halo. In our most recent work in FY2019, we have found that this uncertainty can be reduced using satellite galaxies instead of halo stars. Despite the small number of available satellites compared to halo stars, satellites have a dynamical state that is closer to steady-state than halo stars, thus exhibiting a smaller systematic bias. Starting from this we have further developed a universal model for the phasespace distribution of satellites from a large sample of simulated halos. Fitting this new model to a most recent sample of satellite galaxies with GAIA proper motions, we are able to get the most accurate measurement of the Milky Way halo mass.
We have also carried out an extensive review on the Milky Way mass measurements in the literature, providing a consistent and up-to-date view of the subject.These progresses can provide a good foundation for further near field cosmological studies on the property of dark matterand their small scaledistributions.
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