The connection between the host halo and the satellite galaxies of the Milky Way

Abstract

Many properties of the Milky Way's dark matter halo, including its mass assembly history, concentration, and subhalo population, remain poorly constrained. We explore the connection between these properties of the Milky Way and its satellite galaxy population, especially the implication of the presence of the Magellanic Clouds for the properties of the Milky Way halo. Using a suite of high-resolution $N$-body simulations of Milky Way-mass halos with a fixed final Mvir ~ 10^{12.1}Msun, we find that the presence of Magellanic Cloud-like satellites strongly correlates with the assembly history, concentration, and subhalo population of the host halo, such that Milky Way-mass systems with Magellanic Clouds have lower concentration, more rapid recent accretion, and more massive subhalos than typical halos of the same mass. Using a flexible semi-analytic galaxy formation model that is tuned to reproduce the stellar mass function of the classical dwarf galaxies of the Milky Way with Markov-Chain Monte-Carlo, we show that adopting host halos with different mass-assembly histories and concentrations can lead to different best-fit models for galaxy-formation physics, especially for the strength of feedback. These biases arise because the presence of the Magellanic Clouds boosts the overall population of high-mass subhalos, thus requiring a different stellar-mass-to-halo-mass ratio to match the data. These biases also lead to significant differences in the mass--metallicity relation, the kinematics of low-mass satellites, the number counts of small satellites associated with the Magellanic Clouds, and the stellar mass of Milky Way itself. Observations of these galaxy properties can thus provide useful constraints on the properties of the Milky Way halo.

20 pages, 12 figures, accepted for publication in ApJ. A new section on the effect of host halo mass-assembly history on the central galaxy stellar mass is added

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Cited by in corpus (23)

• The SAGA Survey: I. Satellite Galaxy Populations Around Eight Milky Way Analogs
• Milky Way Satellite Census. II. Galaxy--Halo Connection Constraints Including the Impact of the Large Magellanic Cloud
• Gravitational probes of dark matter physics
• The Dragonfly Nearby Galaxies Survey. III. The Luminosity Function of the M101 Group
• SatGen: a semi-analytical satellite galaxy generator -- I. The model and its application to Local-Group satellite statistics
• The predicted luminous satellite populations around SMC and LMC-mass galaxies - A missing satellite problem around the LMC?
• Modeling the Connection Between Subhalos and Satellites in Milky Way-like Systems
• Predicted Extension of the Sagittarius Stream to the Milky Way Virial Radius
• Modeling the Impact of Baryons on Subhalo Populations with Machine Learning
• Luminosity Functions and Host-to-Host Scatter of Dwarf Satellite Systems in the Local Volume
• Symphony: Cosmological Zoom-in Simulation Suites over Four Decades of Host Halo Mass
• An observer's guide to the (Local Group) dwarf galaxies: predictions for their own dwarf satellite populations
• The impact of stellar and AGN feedback on halo-scale baryonic and dark matter accretion in the EAGLE simulations
• Radial Distributions of Dwarf Satellite Systems in the Local Volume
• Upper Limit on the Milky Way Mass from the Orbit of the Sagittarius Dwarf Satellite
• The importance of preventive feedback: inference from observations of the stellar masses and metallicities of Milky Way dwarf galaxies
• How cosmological merger histories shape the diversity of stellar haloes
• A new calibration method of sub-halo orbital evolution for semi-analytic models
• Milky Way-est: Cosmological Zoom-in Simulations with Large Magellanic Cloud and Gaia-Sausage-Enceladus Analogs
• The effect of Large Magellanic Cloud on the satellite galaxy population in Milky Way analogous Galaxies
• The multi-component fitting to the star formation histories in the TNG simulation
• Probabilistic Inference of the Structure and Orbit of Milky Way Satellites with Semi-Analytic Modeling
• Forward-modelling the Luminosity, Distance, and Size distributions of the Milky Way Satellites