| 研究実績の概要 |
I have taken advantage of the Subaru Telescope, Hyper-Supreme Cam (HSC) to make precise proper motion measurements to explore those faint and high proper motion objects, combining with the Sloan Digital Sky Survey (SDSS). I have established a white dwarf catalogue by applying the reduced proper motion diagram to separate the white dwarf from the main-sequence stars. A black-body spectroscopic fitting has also been adopted to make validation and derive the temperature of white dwarfs, especially the low-temperature ones which can hardly be fitted with white dwarfs H/He models.
I have find a lot of extremely low-temperature white dwarf candidates lower than 5,000K. They are supposed to be the oldest population of stars, the fossil of our Milky Way Galaxy. We can measure the property of the white dwarfs to probe the information of the early time of the Galaxy. Besides, we can perfect the white dwarf cooling model at the red end.
Based on the white dwarf catalogue, I have made the white dwarf luminosity function (WDLF), which has been developed to recover the age and star formation history, such as that star burst will appear as a bump in the WDLF. Our WDLF shows a potential to include the intrinsic faint white dwarfs which has never been discovered in previous work.
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| 今後の研究の推進方策 |
The following work is still on white dwarfs, I will try to probe the information from our white dwarf luminosity function. The star forming history is one of the most interesting destinations. We can trace the property of the stars in the early age. If we can confirm the low-temperature white dwarfs, I can support the data evidence to perfect the current white dwarf models for the oldest ones. The halo white dwarfs are also a good sample to study which are easier to distinguish from others due to the high proper motion, if we can find a coherent motion and similar properties such as metallicity. If it is possible, I am also planning to probe individual white dwarf with abnormal behaviours, such as weird motion, etc.
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