Galaxies lacking dark matter in the Illustris simulation

Haslbauer, Moritz; Dabringhausen, J.; Kroupa, Pavel; Javanmardi, Behnam; Banik, Indranil

doi:10.1051/0004-6361/201833771

Cited by 45 publications

(64 citation statements)

References 93 publications

(188 reference statements)

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“…The only presently known, viable physical process capable of forming highly phase-space correlated systems of dwarf galaxies and star clusters, including counter-orbiting satellites, is their formation in gas-rich tidal tails of interacting galaxies (Pawlowski et al 2011;Fouquet et al 2012;Yang et al 2014). However, such tidal dwarf galaxies are dark-matter free in a ΛCDM universe (Ploeckinger et al 2018;Haslbauer et al 2019). This is at odds with the high mass-to-light ratios of many of the observed dwarf satellite galaxies, unless the dark matter hypothesis is abandoned in favor of a modified gravity approach (Bílek et al 2018;Banik et al 2018).…”

Section: Introductionmentioning

confidence: 99%

The Milky Way’s disc of classical satellite galaxies in light of Gaia DR2

Pawlowski

Kroupa

2019

Monthly Notices of the Royal Astronomical Society

107

100

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We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structure, the plane (or disk) of satellite galaxies defined by their positions. The orbital planes of eight satellites align to < 20 • with a common direction, seven even orbit in the same sense. Most also share similar specific angular momenta, though their wide distribution on the sky does not support a recent group infall or satellitesof-satellites origin. The orbital pole concentration has continuously increased as more precise proper motions were measured, as expected if the underlying distribution shows true correlation that is washed out by observational uncertainties. The orbital poles of the up to seven most correlated satellites are in fact almost as concentrated as expected for the best-possible orbital alignment achievable given the satellite positions. Combining the best-available proper motions substantially increases the tension with ΛCDM cosmological expectations: < 0.1 per cent of simulated satellite systems in IllustrisTNG contain seven orbital poles as closely aligned as observed. Simulated systems that simultaneously reproduce the concentration of orbital poles and the flattening of the satellite distribution have a frequency of < 0.1 per cent for any number of k > 3 combined orbital poles, indicating that these results are not affected by a look-elsewhere effect. This compounds the Planes of Satellite Galaxies Problem.

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Section: Introductionmentioning

confidence: 99%

The Milky Way’s disc of classical satellite galaxies in light of Gaia DR2

Pawlowski

Kroupa

2019

Monthly Notices of the Royal Astronomical Society

107

100

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“…In the standard hierarchical bottom-up cosmological model, dwarf galaxies void of dark matter are formed in the overdensities of tidal tails and arms during interactions of massive galaxies. The high velocity dispersion of dark matter particles and the relatively shallow gravitational potential compared to their host galaxy prevent tidal dwarf galaxies (TDGs) to capture a significant amount of dark matter (Barnes & Hernquist 1992;Bournaud & Duc 2006;Wetzstein et al 2007;Bournaud et al 2008a,b;Fouquet et al 2012;Yang et al 2014;Ploeckinger et al 2018;Haslbauer et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The Dual Dwarf Theorem states that in any viable cosmological model, interactions between galaxies imply that E-mail: mhaslbauer@astro.uni-bonn.de (MH) both primordial and TDGs must exist. In particular, the lambda cold dark matter (ΛCDM) cosmological model predicts both dark-matter-dominated dwarf galaxies and darkmatter-lacking TDGs with different observed stellar halfmass radii (Kroupa et al 2010;Kroupa 2012;Dabringhausen & Kroupa 2013;Haslbauer et al 2019). The former are primordial galaxies formed by the condensation of gas in dark matter halos.…”

Section: Introductionmentioning

confidence: 99%

“…Dark-matter-dominated and dark-matter-poor dwarf galaxies (i.e. TDGs) are distinguishable in a radiusmass plane, because TDGs are formed naked without the help of dark matter and have to be therefore more compact in order to remain gravitationally bound (Kroupa 2012;Dabringhausen & Kroupa 2013;Haslbauer et al 2019). Ploeckinger et al (2018) demonstrated that TDGs can be found in the self-consistent cosmological EAGLE simulation and the study of TDG formation in the Illustris-1 sim-ulation by Haslbauer et al (2019) contains a very detailed analysis of their properties as well as of resolution issues.…”

Section: Introductionmentioning

confidence: 99%

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The ultra-diffuse dwarf galaxies NGC 1052-DF2 and 1052-DF4 are in conflict with standard cosmology

Haslbauer

Banik

Kroupa

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Recently van Dokkum et al. (2018b) reported that the galaxy NGC 1052-DF2 (DF2) lacks dark matter if located at 20 Mpc from Earth. In contrast, DF2 is a dark-matterdominated dwarf galaxy with a normal globular cluster population if it has a much shorter distance near 10 Mpc. However, DF2 then has a high peculiar velocity wrt. the cosmic microwave background of 886 km s −1 , which differs from that of the Local Group (LG) velocity vector by 1298 km s −1 with an angle of 117 • . Taking into account the dynamical M/L ratio, the stellar mass, half-light radius, peculiar velocity, motion relative to the LG, and the luminosities of the globular clusters, we show that the probability of finding DF2-like galaxies in the lambda cold dark matter (ΛCDM) TNG100-1 simulation is at most 1.0×10 −4 at 11.5 Mpc and is 4.8×10 −7 at 20.0 Mpc. At 11.5 Mpc, the peculiar velocity is in significant tension with the TNG100-1, TNG300-1, and Millennium simulations, but occurs naturally in a Milgromian cosmology. At 20.0 Mpc, the unusual globular cluster population would challenge any cosmological model. Estimating that precise measurements of the internal velocity dispersion, stellar mass, and distance exist for 100 galaxies, DF2 is in 2.6σ (11.5 Mpc) and 4.1σ (20.0 Mpc) tension with standard cosmology. Adopting the former distance for DF2 and assuming that NGC 1052-DF4 is at 20.0 Mpc, the existence of both is in tension at ≥ 4.8σ with the ΛCDM model. If both galaxies are at 20.0 Mpc the ΛCDM cosmology has to be rejected by ≥ 5.8σ.

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“…Nusser 2018), as well as for alternative models of gravity (e.g. Famaey et al 2018;Haslbauer et al 2019;Haghi et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The globular cluster population of NGC 1052-DF2: evidence for rotation

Lewis

Brewer

Wan

2019

Monthly Notices of the Royal Astronomical Society: Letters

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Based upon the kinematics of ten globular clusters, it has recently been claimed that the ultra-diffuse galaxy, NGC 1052-DF2, lacks a significant quantity of dark matter. Dynamical analyses have generally assumed that this galaxy is pressure supported, with the relatively small velocity dispersion of the globular cluster population indicating the deficit of dark matter. However, the presence of a significant rotation of the globular cluster population could substantially modify this conclusion. Here we present the discovery of such a signature of rotation in the kinematics of NGC 1052-DF2's globular clusters, with a velocity amplitude of ∼ 12.44 +4.40 −5.16 km/s, which, through Bayesian model comparison, represents a marginally better fit to the available kinematic data; note that this rotation is distinct from, and approximately perpendicular to, the recently identified rotation of the stellar component of NGC 1052-DF2. Assuming this truly represents an underlying rotation, it is shown that the determined mass depends upon the inclination of the rotational component and, with a moderate inclination, the resultant mass to light ratio can exceed M/L ∼ 10.

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Galaxies lacking dark matter in the Illustris simulation

Cited by 45 publications

References 93 publications

The Milky Way’s disc of classical satellite galaxies in light of Gaia DR2

The Milky Way’s disc of classical satellite galaxies in light of Gaia DR2

The ultra-diffuse dwarf galaxies NGC 1052-DF2 and 1052-DF4 are in conflict with standard cosmology

The globular cluster population of NGC 1052-DF2: evidence for rotation

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