@article{84a1c88764b3492abcf4829f86ba484c,
title = "NIHAO V: Too big does not fail-reconciling the conflict between ΛCDM predictions and the circular velocities of nearby field galaxies",
abstract = "We compare the half-light circular velocities, V1/2, of dwarf galaxies in the Local Group to the predicted circular velocity curves of galaxies in the Numerical Investigations of Hundred Astrophysical Objects (NIHAO) suite of Λ cold dark matter (ΛCDM) simulations. We use a subset of 34 simulations in which the central galaxy has a stellar luminosity in the range 0.5×105 <LV/L⊙ <2×108. The NIHAOgalaxy simulations reproduce the relation between stellar mass and halo mass from abundance matching, as well as the observed half-light size versus luminosity relation. The corresponding dissipationless simulations overpredict the V1/2, recovering the problem known as too big to fail (TBTF). By contrast, the NIHAO simulations have expanded dark matter haloes, and provide an excellent match to the distribution of V1/2 for galaxies with LV ≥ 2 × 106 L⊙. For lower luminosities, our simulations predict very little halo response, and tend to overpredict the observed circular velocities. In the context of ΛCDM, this could signal the increased stochasticity of star formation in haloes below Mhalo ~ 1010M⊙, or the role of environmental effects. Thus, haloes that are 'TBTF', do not fail ΛCDM, but haloes that are 'too small to pass' (the galaxy formation threshold) provide a future test of ΛCDM.",
keywords = "Cosmology: theory, Dark matter, Galaxies: dwarf, Galaxies: haloes, Galaxies: kinematics and dynamics, Local group",
author = "Dutton, {Aaron A.} and Macci{\`o}, {Andrea V.} and Jonas Frings and Liang Wang and Stinson, {Gregory S.} and Camilla Penzo and Xi Kang",
note = "Funding Information: We thank the referee for a prompt and constructive report. The simulations were performed on the THEO cluster of the Max-Planck- Institut f{\"u}r Astronomie and the HYDRA cluster at the Rechenzentrum in Garching; and the Milky Way supercomputer, funded by the Deutsche Forschungsgemeinschaft (DFG) through Collaborative Research Center (SFB 881) ''The Milky Way System'' (subproject Z2), hosted and co-funded by the J{\"u}lich Supercomputing Center (JSC). We greatly appreciate the contributions of all these computing allocations. AAD, AVM and GSS acknowledge support through the Sonderforschungsbereich SFB 881 ''The Milky Way System'' (subprojects A1 and A2) of the German Research Foundation (DFG). JF acknowledges funding through the graduate college Astrophysics of cosmological probes of gravity by Landesgraduiertenakademie Baden-W{\"u}rttemberg. LW acknowledges support of the MPG-CAS student programme. GSS acknowledges funding from the European Research Council under the European Union''s Seventh Framework Programme (FP 7) ERC Grant Agreement no. [321035]. XK acknowledge the support from NSFC project No.11333008 and the ''Strategic Priority Research Program the Emergence of Cosmological Structures'' of the CAS(No.XD09010000). Publisher Copyright: {\textcopyright} 2016 The Authors.",
year = "2016",
month = jan,
day = "7",
doi = "10.1093/mnrasl/slv193",
language = "English (US)",
volume = "457",
pages = "L74--L78",
journal = "Monthly Notices of the Royal Astronomical Society: Letters",
issn = "1745-3925",
publisher = "Oxford University Press",
number = "1",
}