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Title: The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies

Abstract

Dwarf galaxies are known to have remarkably low star formation efficiency due to strong feedback. Adopting the dwarf galaxies of the Milky Way (MW) as a laboratory, we explore a flexible semi-analytic galaxy formation model to understand how the feedback processes shape the satellite galaxies of the MW. Using Markov Chain Monte Carlo, we exhaustively search a large parameter space of the model and rigorously show that the general wisdom of strong outflows as the primary feedback mechanism cannot simultaneously explain the stellar mass function and the mass–metallicity relation of the MW satellites. An extended model that assumes that a fraction of baryons is prevented from collapsing into low-mass halos in the first place can be accurately constrained to simultaneously reproduce those observations. The inference suggests that two different physical mechanisms are needed to explain the two different data sets. In particular, moderate outflows with weak halo mass dependence are needed to explain the mass–metallicity relation, and prevention of baryons falling into shallow gravitational potentials of low-mass halos (e.g., “pre-heating”) is needed to explain the low stellar mass fraction for a given subhalo mass.

Authors:
; ; ;  [1];  [2];  [3];  [4];  [5]
  1. The Observatories, The Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  2. Department of Physics and Astronomy and the Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, Pittsburgh, PA 15260 (United States)
  3. CCAPP and Department of Physics, The Ohio State University, 191 W. Woodruff Avenue, Columbus, OH 43210 (United States)
  4. Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)
  5. Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA 94305 (United States)
Publication Date:
OSTI Identifier:
22663175
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 846; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; BARYONS; FEEDBACK; GALAXIES; MARKOV PROCESS; MASS; METALLICITY; MILKY WAY; MONTE CARLO METHOD; SATELLITES; SPACE; STAR EVOLUTION; STARS

Citation Formats

Lu, Yu, Benson, Andrew, Wetzel, Andrew, Tonnesen, Stephanie, Mao, Yao-Yuan, Peter, Annika H. G., Boylan-Kolchin, Michael, and Wechsler, Risa H. The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA845E.
Lu, Yu, Benson, Andrew, Wetzel, Andrew, Tonnesen, Stephanie, Mao, Yao-Yuan, Peter, Annika H. G., Boylan-Kolchin, Michael, & Wechsler, Risa H. The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies. United States. doi:10.3847/1538-4357/AA845E.
Lu, Yu, Benson, Andrew, Wetzel, Andrew, Tonnesen, Stephanie, Mao, Yao-Yuan, Peter, Annika H. G., Boylan-Kolchin, Michael, and Wechsler, Risa H. Fri . "The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies". United States. doi:10.3847/1538-4357/AA845E.
@article{osti_22663175,
title = {The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies},
author = {Lu, Yu and Benson, Andrew and Wetzel, Andrew and Tonnesen, Stephanie and Mao, Yao-Yuan and Peter, Annika H. G. and Boylan-Kolchin, Michael and Wechsler, Risa H.},
abstractNote = {Dwarf galaxies are known to have remarkably low star formation efficiency due to strong feedback. Adopting the dwarf galaxies of the Milky Way (MW) as a laboratory, we explore a flexible semi-analytic galaxy formation model to understand how the feedback processes shape the satellite galaxies of the MW. Using Markov Chain Monte Carlo, we exhaustively search a large parameter space of the model and rigorously show that the general wisdom of strong outflows as the primary feedback mechanism cannot simultaneously explain the stellar mass function and the mass–metallicity relation of the MW satellites. An extended model that assumes that a fraction of baryons is prevented from collapsing into low-mass halos in the first place can be accurately constrained to simultaneously reproduce those observations. The inference suggests that two different physical mechanisms are needed to explain the two different data sets. In particular, moderate outflows with weak halo mass dependence are needed to explain the mass–metallicity relation, and prevention of baryons falling into shallow gravitational potentials of low-mass halos (e.g., “pre-heating”) is needed to explain the low stellar mass fraction for a given subhalo mass.},
doi = {10.3847/1538-4357/AA845E},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 846,
place = {United States},
year = {2017},
month = {9}
}