A Rich Satellite Population of the NGC 4437 Group and Implications of a Magnitude Gap for Galaxy Group Assembly History

Abstract

Both observations and cosmological simulations have recently shown that there is a large scatter in the number of satellites of Milky Way (MW)-like galaxies. In this study, we investigate the relation between the satellite number and galaxy group assembly history, using the $r-$band magnitude gap ($\Delta m_{12}$) between the first and the second brightest galaxy as an indicator. From 20 deg${}^2$ of Hyper Suprime-Cam Subaru Strategic Program Wide layer, we identify 17 dwarf satellite candidates around NGC 4437, a spiral galaxy with about one-fourth of the MW stellar mass. We estimate their distances using the surface brightness fluctuation (SBF) method. Then we confirm five candidates as members of the NGC 4437 group, resulting in a total of seven group members. Combining the NGC 4437 group (with $\Delta m_{12}=2.5$ mag) with other groups in the literature, we find a stratification of the satellite number by $\Delta m_{12}$ for a given host stellar mass. The satellite number for given host stellar mass decreases as $\Delta m_{12}$ increases. The same trend is found in simulated galaxy groups in IllustrisTNG50 simulations. We also find that the host galaxies in groups with a smaller $\Delta m_{12}$ (like NGC 4437) have assembled their halo mass more recently than those in larger gap groups, and that their stellar-to-halo mass ratios (SHMRs) increase as $\Delta m_{12}$ increases. These results show that the large scatter in the satellite number is consistent with a large range of $\Delta m_{12}$, indicating diverse group assembly histories.

24 pages, 16 figures, Accepted for publication in ApJ

References in corpus (25)

• Updated Nearby Galaxy Catalog
• The SAGA Survey. II. Building a Statistical Sample of Satellite Systems around Milky Way-like Galaxies
• The Hubble Constant from Infrared Surface Brightness Fluctuation Distances
• The PAndAS view of the Andromeda satellite system - II. Detailed properties of 23 M31 dwarf spheroidal galaxies
• Discovery of New Dwarf Galaxies in the M81 Group
• First results from the MADCASH Survey: A Faint Dwarf Galaxy Companion to the Low Mass Spiral Galaxy NGC 2403 at 3.2 Mpc
• Discovery of a close pair of faint dwarf galaxies in the halo of Centaurus A
• The Dragonfly Nearby Galaxies Survey. III. The Luminosity Function of the M101 Group
• Discovery of diffuse dwarf galaxy candidates around M101
• The abundance of satellites around Milky Way- and M31-like galaxies with the TNG50 simulation: a matter of diversity
• Luminosity Functions and Host-to-Host Scatter of Dwarf Satellite Systems in the Local Volume
• Can cosmological simulations capture the diverse satellite populations of observed Milky Way analogues?
• Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: Calibration and Methodology
• Newly discovered dwarf galaxies in the MATLAS low density fields
• Radial Distributions of Dwarf Satellite Systems in the Local Volume
• Ultimate age-dating method for galaxy groups; clues from the Millennium Simulations
• The LBT Satellites of Nearby Galaxies Survey (LBT-SONG): The Satellite Population of NGC 628
• A comparative study of satellite galaxies in Milky Way-like galaxies from HSC, DECaLS and SDSS
• Hubble Space Telescope Observations of Two Faint Dwarf Satellites of Nearby LMC Analogs from MADCASH
• Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: the Complete Satellite System of M101
• Determination of the Local Hubble Constant from Virgo Infall Using TRGB Distances
• A Survey of Satellite Galaxies around NGC 4258
• Are fossil groups early-forming galaxy systems?
• Calibration of Surface Brightness Fluctuations for Dwarf Galaxies in the Hyper Suprime-Cam $gi$ Filter System
• The Luminosity Functions and Redshift Evolution of Satellites of Low-Mass Galaxies in the COSMOS Survey

Cited by in corpus (2)

• Saying Hallo to M94's Stellar Halo: Investigating the Accretion History of the Largest Pseudobulge Host in the Local Universe
• The Exploration of Local VolumE Satellites (ELVES) Survey: A Nearly Volume-Limited Sample of Nearby Dwarf Satellite Systems