Oral Presentation

Statistical Verification of the Missing Satellites Problem outside the Local Group

Author(s): Masashi Nashimoto (NAOJ), Masayuki Tanaka (NAOJ), Masashi Chiba (Tohoku Univ.), Kohei Hayashi (NIT, Ichinoseki college), Yutaka Komiyama (NAOJ)

Presenter: Masashi Nashimoto (NAOJ)

The Lambda cold dark matter (LCDM) model is a standard cosmological model that successfully describes the large-scale structure of the universe. On the other hand, the number of dwarf galaxies in the Local Group (LG) expected from the LCDM framework is inconsistent with observations. There is no consensus on whether this discrepancy, known as the missing satellites problem (MSP), is universal even outside the LG.
This study statistically verifies the MSP by detecting dwarf galaxies around seven nearby galaxies outside the LG using Hyper Suprime-Cam data. We compare the detected dwarf galaxies with the Milky Way (MW) satellites and other dwarf galaxies outside the LG and find similar trends in the luminosity function and size-luminosity relation. On the other hand, the spatial distribution shows different trends inside and outside the LG. Therefore, we suspect that the MW may not be a typical galaxy regarding dwarf galaxies.