Due to the strong tidal forces of supermassive black holes (SMBHs), standard star formation should be suppressed at a distance of < 0.1 pc from the SMBHs. However, dozens of stars have been found around the Galactic SMBH, Sgr A*. The origin of these stars has continued to be of great interest for the last decades. Recently, Nishiyama et al. (2024) found a very interesting, low metal-abundance star called S0-6 in the vicinity of Sgr A*. The similarity in abundances suggests that S0-6 was born in a dwarf galaxy that was orbiting our Galaxy in the past. However, a lone star is unable to reach the core of a galaxy, and it can only do so if it is a member of a massive star cluster. Here we propose near-infrared, high-resolution (R ∼ 20,000) spectroscopy of 25 late-type giants around Sgr A*, to search for additional stars originating from a dwarf galaxy. This will provide valuable insight into the assembly history of our Galaxy. Our second goal is to construct a metallicity distribution function for the first time, which will help unveiling the origin of the stars around Sgr A* and the formation history of the nuclear star cluster. We will observe 12 giants in this semester, and the rest in the following semesters.
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