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A profile in FIRE: resolving the radial distributions of satellite galaxies in the Local Group with simulations

Samuel, Jenna and Wetzel, Andrew and Tollerud, Erik and Garrison-Kimmel, Shea and Loebman, Sarah and El-Badry, Kareem and Hopkins, Philip F. and Boylan-Kolchin, Michael and Faucher-Giguère, Claude-André and Bullock, James S. and Benincasa, Samantha and Bailin, Jeremy (2019) A profile in FIRE: resolving the radial distributions of satellite galaxies in the Local Group with simulations. . (Unpublished)

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While many tensions between Local Group (LG) satellite galaxies and LCDM cosmology have been alleviated through recent cosmological simulations, the spatial distribution of satellites remains an important test of physical models and physical versus numerical disruption in simulations. Using the FIRE-2 cosmological zoom-in baryonic simulations, we examine the radial distributions of satellites with M⋆ > 10^5 M⊙ around 8 isolated Milky Way- (MW) mass host galaxies and 4 hosts in LG-like pairs. We demonstrate that these simulations resolve the survival and physical destruction of satellites with M⋆ ≳ 10^5 M⊙. The simulations broadly agree with LG observations, spanning the radial profiles around the MW and M31. This agreement does not depend strongly on satellite mass, even at distances ≾ 100 kpc. Host-to-host variation dominates the scatter in satellite counts within 300 kpc of the hosts, while time variation dominates scatter within 50 kpc. More massive host galaxies within our sample have fewer satellites at small distances, because of enhanced tidal destruction of satellites via the baryonic disks of host galaxies. Furthermore, we quantify and provide fits to the tidal depletion of subhalos in baryonic relative to dark matter-only simulations as a function of distance. Our simulated profiles imply observational incompleteness in the LG even at M⋆ ≳ 10^5 M⊙: we predict 2-10 such satellites to be discovered around the MW and possibly 6-9 around M31. To provide cosmological context, we compare our results with the radial profiles of satellites around MW analogs in the SAGA survey, finding that our simulations are broadly consistent with most SAGA systems.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Samuel, Jenna0000-0002-8429-4100
Wetzel, Andrew0000-0003-0603-8942
Tollerud, Erik0000-0002-9599-310X
Garrison-Kimmel, Shea0000-0002-4655-8128
El-Badry, Kareem0000-0002-6871-1752
Hopkins, Philip F.0000-0003-3729-1684
Boylan-Kolchin, Michael0000-0002-9604-343X
Faucher-Giguère, Claude-André0000-0002-4900-6628
Bullock, James S.0000-0003-4298-5082
Additional Information:We thank Marla Geha, Risa Wechsler, and Ethan Nadler for their helpful comments. This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013, 2018), the IPython package (Pérez & Granger 2007), NumPy (Van Der Walt et al. 2011), SciPy (Jones et al. 2001), Numba (Lam et al. 2015), and matplotlib, a Python library for publication quality graphics (Hunter 2007). JS, AW, and SB were supported by NASA, through ATP grant 80NSSC18K1097 and HST grants GO-14734 and AR-15057 from the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. We performed this work in part at the Aspen Center for Physics, supported by NSF grant PHY-1607611, and at the KITP, supported NSF grant PHY-1748958. Support for SGK and PFH was provided by an Alfred P. Sloan Research Fellowship, NSF grant #1715847 and CAREER grant #1455342, and NASA grants NNX15AT06G, JPL 1589742, 17-ATP17-0214. Support for SRL was provided by NASA through Hubble Fellowship grant #HST-JF2-51395.001-A awarded by STScI. KE was supported by an NSF graduate research fellowship. 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 STScI. CAFG was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grant 17-ATP17-0067, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. JSB was supported by NSF AST- 1518291, HST-AR-14282, and HST-AR-13888. We ran simulations using the Extreme Science and Engineering Discovery Environment (XSEDE) supported by NSF grant ACI- 1548562, Blue Waters via allocation PRAC NSF.1713353 supported by the NSF, and NASA HEC Program through the NAS Division at Ames Research Center.
Funding AgencyGrant Number
NASA Hubble FellowshipGO-14734
NASA Hubble FellowshipAR-15057
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
NASA Hubble FellowshipHST-JF2-51395.001-A
NSF Graduate Research FellowshipUNSPECIFIED
NASA Hubble FellowshipAR-13888
NASA Hubble FellowshipAR-13896
NASA Hubble FellowshipAR-14282
NASA Hubble FellowshipAR-14554
NASA Hubble FellowshipAR-15006
NASA Hubble FellowshipGO-12914
NASA Hubble FellowshipGO-14191
Research Corporation for Science AdvancementUNSPECIFIED
Subject Keywords:galaxies: dwarf - galaxies: Local Group - galaxies: formation - methods: numerical
Record Number:CaltechAUTHORS:20190726-095255751
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97439
Deposited By: Tony Diaz
Deposited On:26 Jul 2019 17:22
Last Modified:15 Nov 2019 03:59

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