期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 497, 期 2, 页码 2393-2417出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/staa2101
关键词
galaxies: evolution; galaxies: formation; dark matter
资金
- National Science Foundation (NSF) [AST-1910965]
- NSF CAREER [AST-1752913]
- NSF [AST-1910346, AST-1715101, OCI-1053575, AST-1517491, AST-1715216, AST-1652522]
- NASA [NNX17AG29G, NAS5-26555, 17-ATP17-0067]
- Space Telescope Science Institute [HST-AR-14282, HST-AR-14554, HST-AR-15006, HST-GO-14191, HST-GO-15658]
- STFC [ST/T000244]
- McDonald Observatory at the University of Texas at Austin
- NASA through ATP [80NSSC18K1097]
- HST from STScI [GO-14734, AR-15057, AR-15809, GO-15902]
- Heising-Simons Foundation
- Hellman Foundation
- NSF
- NASA by STScI [10938]
- Research Corporation for Science Advancement
We analyse the cold dark matter density profiles of 54 galaxy haloes simulated with Feedback In Realistic Environments (FIRE)-2 galaxy formation physics, each resolved within 0.5 per cent of the halo virial radius. These haloes contain galaxies with masses that range from ultrafaint dwarfs (M-star similar to 10(4.5) M-circle dot) to the largest spirals (M-star similar or equal to 10(11) M-circle dot) and have density profiles that are both cored and cuspy. We characterize our results using a new, analytic density profile that extends the standard two-parameter Einasto form to allow for a pronounced constant density core in the resolved innermost radius. With one additional core-radius parameter, r(c), this three-parameter core-Einasto profile is able to characterize our feedback-impacted dark matter haloes more accurately than other three-parameter profiles proposed in the literature. To enable comparisons with observations, we provide fitting functions for r(c) and other profile parameters as a function of both M-star and M-star/M-halo. In agreement with past studies, we find that dark matter core formation is most efficient at the characteristic stellar-to-halo mass ratio M-star/M-halo similar or equal to 5 x 10(-3), or M-star similar to 10(9) M-circle dot, with cores that are roughly the size of the galaxy half-light radius, r(c) similar or equal to 1-5 kpc. Furthermore, we find no evidence for core formation at radii greater than or similar to 100 pc in galaxies with M-star/M-halo < 5 x 10(-4) or M-star less than or similar to 10(6) M-circle dot. For Milky Way-size galaxies, baryonic contraction often makes haloes significantly more concentrated and dense at the stellar half-light radius than DMO runs. However, even at the Milky Way scale, FIRE-2 galaxy formation still produces small dark matter cores of similar or equal to 0.5-2 kpc in size. Recent evidence for a similar to 2 kpc core in the Milky Way's dark matter halo is consistent with this expectation.
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