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Published August 2019 | Submitted + Published
Journal Article Open

Phat ELVIS: The inevitable effect of the Milky Way's disc on its dark matter subhaloes

Abstract

We introduce an extension of the ELVIS project to account for the effects of the Milky Way galaxy on its subhalo population. Our simulation suite, Phat ELVIS, consists of 12 high-resolution cosmological dark matter-only (DMO) zoom simulations of Milky Way-size ΛCDM haloes [M_v = (0.7−2) × 10^(12) M⊙] along with 12 re-runs with embedded galaxy potentials grown to match the observed Milky Way disc and bulge today. The central galaxy potential destroys subhalos on orbits with small pericentres in every halo, regardless of the ratio of galaxy mass to halo mass. This has several important implications. (1) Most of the Discruns have no subhaloes larger than V_(max) = 4.5 km s^(-1) within 20 kpc and a significant lack of substructure going back ∼8 Gyr, suggesting that local stream-heating signals from dark substructure will be rare. (2) The pericentre distributions of Milky Way satellites derived from Gaia data are remarkably similar to the pericentre distributions of subhaloes in the Disc runs, while the DMO runs drastically overpredict galaxies with pericentres smaller than 20 kpc. (3) The enhanced destruction produces a tension opposite to that of the classic 'missing satellites' problem: in order to account for ultra-faint galaxies known within 30 kpc of the Galaxy, we must populate haloes with V_(peak) ≃ 7 km s^(-1)(M ≃ 3 × 10^7 M⊙ at infall), well below the atomic cooling limit of V_(peak)≃16kms^(-1) (M ≃ 5 × 10^8M⊙ at infall). (4) If such tiny haloes do host ultra-faint dwarfs, this implies the existence of ∼1000 satellite galaxies within 300 kpc of the Milky Way.

Additional Information

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2019 May 7. Received 2019 April 29; in original form 2018 November 21. Published: 10 June 2019. The authors would like to thank Sean Fillingham, Michael Cooper, Alex Drlica-Wagner, Denis Erkal, and Josh Simon for useful discussions. TK and JSB were supported by NSF AST-1518291, HST-AR-14282, and HST-AR-13888. MBK acknowledges support from NSF grant AST-1517226 and CAREER grant AST-1752913 and from NASA grants NNX17AG29G and HST-AR-13888, HST-AR-13896, HST-AR-14282, HST-AR-14554, HST-AR-15006, HST-GO-12914, and HST-GO-14191 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. Support for SGK was provided by NASA through the Einstein Postdoctoral Fellowship grant number PF5-160136 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. MSP acknowledges that support for this work was provided by NASA through Hubble Fellowship grant #HST-HF2-51379.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. AGS was supported by an AGEP-GRS supplement to NSF grant AST-1009973. Numerical business was taken care of in a flash using computational resources of the Texas Advanced Computing Center (TACC; http://www.tacc.utexas.edu), the NASA Advanced Supercomputing (NAS) Division and the NASA Center for Climate Simulation (NCCS), and the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number OCI-1053575. This work also made use of Astropy,6 a community-developed core python package for Astronomy (Astropy Collaboration 2013, 2018), MATPLOTLIB (Hunter 2007), NUMPY (van der Walt, Colbert & Varoquaux 2011), SCIPY (Jones et al. 2001), IPYTHON (Perez & Granger 2007), PANDAS (McKinney 2010), MAYAVI (Ramachandran & Varoquaux 2011), and the NASA Astrophysics Data System.

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Additional details

Created:
August 19, 2023
Modified:
October 18, 2023