Structure and Formation of the Andromeda Galactic Halo using Subaru/Hyper Suprime-Cam

2015 Fiscal Year Final Research Report

• Project/Area Number: 25800098
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Tohoku University
• Principal Investigator: Tanaka Mikito 東北大学, 学際科学フロンティア研究所, 助教 (80572057)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 銀河考古学 / 光学赤外線天文学 / 銀河形成 / 宇宙物理 / アンドロメダ銀河 / すばる望遠鏡 / Hyper Suprime-Cam / 近傍銀河

Outline of Final Research Achievements

We have conducted wide-field photometric survey of nearby galactic halos using the Hyper Suprime-Cam (HSC) on the Subaru telescope. In the HSC study of M31's galactic halo, we have developed a method to effectively segregate M31’s RGB stars from foreground contaminations of main-sequence stars of the Milky Way based on HSC’s NB515 filter. Then, we have proceeded with future preparations for a wide-field spectroscopic survey of M31’s halo using Subaru/Prime Focus Spectrograph. On the other hand, in the other HSC study of a nearby galaxy group, we have detected 8 new dwarf galaxy candidates in the outer region of a spiral galaxy, NGC4631, which is under an on-going tidal interaction with an irregular galaxy, NGC4656, and confirmed the three candidates previously reported by Karachentsev et al. 2014. Apparently, these dwarf galaxies are isotropically distributed around NGC4631 (not NGC4656) in contrast to dwarf galaxies of the Milky Way and M31 distributed in a thin plane.

Free Research Field

天文学