TY - JOUR
T1 - Be it therefore resolved
T2 - Cosmological simulations of dwarf galaxies with 30 solar mass resolution
AU - Wheeler, Coral
AU - Hopkins, Philip F.
AU - Pace, Andrew B.
AU - Garrison-Kimmel, Shea
AU - Boylan-Kolchin, Michael
AU - Wetzel, Andrew
AU - Bullock, James S.
AU - Kereš, Dušan
AU - Faucher-Giguère, Claude André
AU - Quataert, Eliot
N1 - Funding Information:
CW is supported by the Lee A. DuBridge Postdoctoral Scholarship in Astrophysics. Support for PFH and SGK was provided by an Alfred P. Sloan Research Fellowship, NSF Collaborative Research Grant #1715847 and CAREER grant #1455342, and NASA grants NNX15AT06G, JPL 1589742, 17-ATP17-0214. ABP acknowledges generous support from the George P. and Cynthia Woods Institute for Fundamental Physics and Astronomy at Texas A&M University. SGK acknowledges additional support by NASA through 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. 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. AW received support from NASA, through ATP grant 80NSSC18K1097 and HST grants GO-14734 and AR-15057 from STScI, and a Hellman Fellowship from UC Davis. CAFG was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grants NNX15AB22G and 17-ATP17-0067, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. Numerical calculations were run on the Caltech compute cluster ‘Wheeler,’ allocations from XSEDE TG-AST130039 and PRAC NSF.1713353 supported by the NSF, and NASA HEC SMD-16-7592.
Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
PY - 2019/12/1
Y1 - 2019/12/1
N2 - We study a suite of extremely high-resolution cosmological Feedback in Realistic Environments simulations of dwarf galaxies (Mhalo ≲ 1010 M☉), run to z = 0 with 30 M☉ resolution, sufficient (for the first time) to resolve the internal structure of individual supernovae remnants within the cooling radius. Every halo with Mhalo ≳ 108.6 M☉ is populated by a resolved stellar galaxy, suggesting very low-mass dwarfs may be ubiquitous in the field. Our ultra-faint dwarfs (UFDs; M∗ < 105 M☉) have their star formation (SF) truncated early (z ≳ 2), likely by reionization, while classical dwarfs (M∗ > 105 M☉) continue forming stars to z < 0.5. The systems have bursty star formation histories, forming most of their stars in periods of elevated SF strongly clustered in both space and time. This allows our dwarf with M∗/Mhalo > 10−4 to form a dark matter core >200 pc, while lower mass UFDs exhibit cusps down to ≲100 pc, as expected from energetic arguments. Our dwarfs with M∗ > 104 M☉ have half-mass radii (R1/2) in agreement with Local Group (LG) dwarfs (dynamical mass versus R1/2 and stellar rotation also resemble observations). The lowest mass UFDs are below surface brightness limits of current surveys but are potentially visible in next-generation surveys (e.g. LSST). The stellar metallicities are lower than in LG dwarfs; this may reflect pre-enrichment of the LG by the massive hosts or Pop-III stars. Consistency with lower resolution studies implies that our simulations are numerically robust (for a given physical model).
AB - We study a suite of extremely high-resolution cosmological Feedback in Realistic Environments simulations of dwarf galaxies (Mhalo ≲ 1010 M☉), run to z = 0 with 30 M☉ resolution, sufficient (for the first time) to resolve the internal structure of individual supernovae remnants within the cooling radius. Every halo with Mhalo ≳ 108.6 M☉ is populated by a resolved stellar galaxy, suggesting very low-mass dwarfs may be ubiquitous in the field. Our ultra-faint dwarfs (UFDs; M∗ < 105 M☉) have their star formation (SF) truncated early (z ≳ 2), likely by reionization, while classical dwarfs (M∗ > 105 M☉) continue forming stars to z < 0.5. The systems have bursty star formation histories, forming most of their stars in periods of elevated SF strongly clustered in both space and time. This allows our dwarf with M∗/Mhalo > 10−4 to form a dark matter core >200 pc, while lower mass UFDs exhibit cusps down to ≲100 pc, as expected from energetic arguments. Our dwarfs with M∗ > 104 M☉ have half-mass radii (R1/2) in agreement with Local Group (LG) dwarfs (dynamical mass versus R1/2 and stellar rotation also resemble observations). The lowest mass UFDs are below surface brightness limits of current surveys but are potentially visible in next-generation surveys (e.g. LSST). The stellar metallicities are lower than in LG dwarfs; this may reflect pre-enrichment of the LG by the massive hosts or Pop-III stars. Consistency with lower resolution studies implies that our simulations are numerically robust (for a given physical model).
KW - Galaxies: dwarf
KW - Galaxies: formation
KW - Galaxies: kinematics and dynamics
KW - Galaxies: star formation
KW - Local Group
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U2 - 10.1093/mnras/stz2887
DO - 10.1093/mnras/stz2887
M3 - Article
AN - SCOPUS:85077566902
SN - 0035-8711
VL - 490
SP - 4447
EP - 4463
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -