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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. Here, 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:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [1]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [6]
  1. The Carnegie Institution for Science, Pasadena, CA (United States)
  2. The Carnegie Institution for Science, Pasadena, CA (United States); California Institute of Technology, Pasadena, CA (United States); Univ. of California, Davis, CA (United States)
  3. Univ. of Pittsburgh, Pittsburgh, PA (United States)
  4. The Ohio State Univ., Columbus, OH (United States)
  5. Univ. of Texas at Austin, Austin, TX (United States)
  6. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1394067
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 846; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: abundances; galaxies: dwarf; galaxies: evolution; galaxies: formation; Galaxy: evolution; Galaxy: formation

Citation Formats

Lu, Yu, Benson, Andrew, Wetzel, Andrew, Mao, Yao -Yuan, Tonnesen, Stephanie, 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, Mao, Yao -Yuan, Tonnesen, Stephanie, 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, Mao, Yao -Yuan, Tonnesen, Stephanie, Peter, Annika H. G., Boylan-Kolchin, Michael, and Wechsler, Risa H.. Thu . "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. https://www.osti.gov/servlets/purl/1394067.
@article{osti_1394067,
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 Mao, Yao -Yuan and Tonnesen, Stephanie 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. Here, 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 = {The Astrophysical Journal (Online)},
number = 1,
volume = 846,
place = {United States},
year = {Thu Aug 31 00:00:00 EDT 2017},
month = {Thu Aug 31 00:00:00 EDT 2017}
}

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