Program: GS-2022A-Q-320

Globular clusters (GCs) play an important role to study the formation and evolution history of the Milky Way (MW), as they have a fossil record of their birthplace. In the case of the MW bulge, however, only a small number of GCs were found at the low-latitude field, and their nature was poorly studied. Recently, an increasing number of stellar clusters were discovered from Gaia and VVV surveys, and Gran et al. (2021) found five interesting GCs associated with the accretion events towards the bulge. In particular, Gran 5 is significant as one of the most metal-poor GC in the bulge ([Fe/H] = -1.56), associated with the Gaia-Enceladus event and also showing bulge-like properties. However, its orbital properties are not clearly overlapped with the other stars and GCs associated with the Gaia-Enceladus. In order to clarify this, a detailed chemical abundance study for Gran 5 is required to confirm the general abundance pattern of accreted objects, such as a low alpha-element abundance ratio. If confirmed, Gran 5 can provide the first evidence that the Gaia-Enceladus event contributed to the formation of the bulge as well as the disk and halo. In addition, we can also study the properties of the Gaia-Enceladus progenitor and multiple stellar populations in Gran 5. In this regard, here we  propose the high-resolution spectroscopy for 7 bright stars in Gran 5 using IGRINS on the Gemini South telescope. Since the low-latitude field of the bulge is hampered by extremely high foreground extinction, IGRINS taking advantage of near-IR high-resolution spectroscopy, as well as covering a wide wavelength range, is the most suitable instrument for detailed chemical studies for bulge GCs. We expect that this program will lead to a better understanding of the metal-poor bulge GCs, formation of the bulge, and assembly process of the Milky Way.