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

Abstract

Many properties of the Milky Way's (MW) dark matter halo, including its mass-assembly history, concentration, and subhalo population, remain poorly constrained. We explore the connection between these properties of the MW and its satellite galaxy population, especially the implication of the presence of the Magellanic Clouds for the properties of the MW halo. Using a suite of high-resolution N-body simulations of MW-mass halos with a fixed final $${M}_{\mathrm{vir}}\sim {10}^{12.1}\,{M}_{\odot }$$, 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 MW-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 MW 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 MW itself. Finally, observations of these galaxy properties can thus provide useful constraints on the properties of the MW halo.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2];  [1]; ORCiD logo [3];  [4]; ORCiD logo [5];  [2]
  1. The Carnegie Institution for Science, Pasadena, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. The Ohio State Univ., Columbus, OH (United States)
  4. The Carnegie Institution for Science, Pasadena, CA (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States)
  5. The Univ. of Texas at Austin, Austin, TX (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1348240
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 830; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: formation; Galaxy: formation; Galaxy: fundamental parameters; Galaxy: halo; Magellanic Clouds

Citation Formats

Lu, Yu, Benson, Andrew, Mao, Yao -Yuan, Tonnesen, Stephanie, Peter, Annika H. G., Wetzel, Andrew R., Boylan-Kolchin, Michael, and Wechsler, Risa H. The connection between the host halo and the satellite galaxies of the Milky Way. United States: N. p., 2016. Web. doi:10.3847/0004-637X/830/2/59.
Lu, Yu, Benson, Andrew, Mao, Yao -Yuan, Tonnesen, Stephanie, Peter, Annika H. G., Wetzel, Andrew R., Boylan-Kolchin, Michael, & Wechsler, Risa H. The connection between the host halo and the satellite galaxies of the Milky Way. United States. doi:10.3847/0004-637X/830/2/59.
Lu, Yu, Benson, Andrew, Mao, Yao -Yuan, Tonnesen, Stephanie, Peter, Annika H. G., Wetzel, Andrew R., Boylan-Kolchin, Michael, and Wechsler, Risa H. Tue . "The connection between the host halo and the satellite galaxies of the Milky Way". United States. doi:10.3847/0004-637X/830/2/59. https://www.osti.gov/servlets/purl/1348240.
@article{osti_1348240,
title = {The connection between the host halo and the satellite galaxies of the Milky Way},
author = {Lu, Yu and Benson, Andrew and Mao, Yao -Yuan and Tonnesen, Stephanie and Peter, Annika H. G. and Wetzel, Andrew R. and Boylan-Kolchin, Michael and Wechsler, Risa H.},
abstractNote = {Many properties of the Milky Way's (MW) dark matter halo, including its mass-assembly history, concentration, and subhalo population, remain poorly constrained. We explore the connection between these properties of the MW and its satellite galaxy population, especially the implication of the presence of the Magellanic Clouds for the properties of the MW halo. Using a suite of high-resolution N-body simulations of MW-mass halos with a fixed final ${M}_{\mathrm{vir}}\sim {10}^{12.1}\,{M}_{\odot }$, 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 MW-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 MW 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 MW itself. Finally, observations of these galaxy properties can thus provide useful constraints on the properties of the MW halo.},
doi = {10.3847/0004-637X/830/2/59},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 830,
place = {United States},
year = {2016},
month = {10}
}

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