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

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. (2017) The Importance of Preventive Feedback: Inference from Observations of the Stellar Masses and Metallicities of Milky Way Dwarf Galaxies. Astrophysical Journal, 846 (1). Art. No. 66. ISSN 1538-4357. doi:10.3847/1538-4357/aa845e.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Lu, Yu0000-0003-2691-1622
Benson, Andrew0000-0001-5501-6008
Wetzel, Andrew0000-0003-0603-8942
Mao, Yao-Yuan0000-0002-1200-0820
Tonnesen, Stephanie0000-0002-8710-9206
Peter, Annika H. G.0000-0002-8040-6785
Boylan-Kolchin, Michael0000-0002-9604-343X
Wechsler, Risa H.0000-0003-2229-011X
Additional Information:© 2017 American Astronomical Society. Received 2017 March 21. Accepted 2017 August 4. Published 2017 August 31. We acknowledge the Ahmanson Foundation for providing computational resources used in this work. The zoom-in simulations were performed using computational resources of SLAC National Accelerator Laboratory and of the National Energy Research Scientific Computing Center. We thank the SLAC computational team for their consistent support. Support for programs HST-AR-13896, HST-AR-13888, HST-AR-13270, HST-AR-12836, and HST-GO-14734 was provided by NASA through a grant from the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. We are grateful to Takashi Okamoto for providing tabulated data for the critical mass as a function of redshift presented in Okamoto et al. (2008). Y.L. thanks Romeel Davé Phil Hopkins, Evan Kirby, Houjun Mo, Josh Simon, and Qingjuan Yu for helpful discussion. A.W. was supported by a Caltech-Carnegie Fellowship, in part through the Moore Center for Theoretical Cosmology and Physics at Caltech. Y.Y.M. is supported by the Samuel P. Langley PITT PACC Postdoctoral Fellowship, and was supported by the Weiland Family Stanford Graduate Fellowship. S.T. was supported by the Alvin E. Nashman Fellowship. M.B.K. acknowledges support from NSF grant AST-1517226 in addition to the HST grants listed above.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
NASANAS 5-26555
Caltech Carnegie FellowshipUNSPECIFIED
Caltech Moore Center for Theoretical Cosmology and PhysicsUNSPECIFIED
Samuel P. Langley PITT PACC Postdoctoral FellowshipUNSPECIFIED
Weiland Family Stanford Graduate FellowshipUNSPECIFIED
Alvin E. Nashman FellowshipUNSPECIFIED
Space Telescope Science InstituteUNSPECIFIED
Subject Keywords:galaxies: abundances; galaxies: dwarf; galaxies: evolution; galaxies: formation; Galaxy: evolution; Galaxy: formation
Issue or Number:1
Record Number:CaltechAUTHORS:20170905-132641863
Persistent URL:
Official Citation:Yu Lu et al 2017 ApJ 846 66
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81142
Deposited By: Ruth Sustaita
Deposited On:05 Sep 2017 22:05
Last Modified:15 Nov 2021 19:41

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