The radial acceleration relation and dark baryons in MOND

Ghari, Amir; Haghi, Hosein; Zonoozi, Akram Hasani

doi:10.1093/mnras/stz1272

Cited by 15 publications

(10 citation statements)

References 67 publications

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“…Besides, a recent study using the data of six deep imaging and spectroscopic surveys shows that the intrinsic scatter of the stellar RAR could be as small as 0.11 dex (Stone & Courteau 2019). Another uncertainty is that the characteristic acceleration in the RAR could decrease by 40% with a scatter around 0.12 dex if we include the effect of cold dark baryons (Ghari, Haghi & Hasani Zonoozi 2019). Therefore, this issue is very complicated and it is still controversial to claim the RAR as tantamount to a natural law (Lelli et al 2017).…”

Section: The Radial Acceleration Relationmentioning

confidence: 99%

The radial acceleration relation in galaxy clusters

Chan

Popolo

2020

Monthly Notices of the Royal Astronomical Society

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Recently, the discovery of the radial acceleration relation (RAR) in galaxies has been regarded as an indirect support of alternative theories of gravity such as Modified Newtonian Dynamics (MOND) and modified gravity. This relation indicates a tight correlation between dynamical mass and baryonic mass in galaxies with different sizes and morphology. However, if the RAR relation is scale-independent and could be explained by alternative theories of gravity, this relation should be universal and true for galaxy clusters as well. In this article, by using the x-ray data of a sample of galaxy clusters, we investigate if there exists any tight correlation between dynamical mass and baryonic mass in galaxy clusters, assuming hot gas mass distribution almost representing baryonic distribution and that the galaxy clusters are virialized. We show that the resulting RAR of 52 non-cool-core galaxy clusters scatters in a large parameter space, possibly due to our simplifying assumptions and unclear matter content in galaxy clusters. This might indicate that the RAR is unlikely to be universal and scale-independent.

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Section: The Radial Acceleration Relationmentioning

confidence: 99%

The radial acceleration relation in galaxy clusters

Chan

Popolo

2020

Monthly Notices of the Royal Astronomical Society

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“…It is challenging to extend the relation any further since measurements must be made either in extremely low-mass, intrinsically faint systems which are currently only observable in close proximity to more massive hosts, or at large distances around more massive systems. In the latter case, eventually the unknown distribution of baryons in the 'warm-hot intergalactic medium', and other difficult-toobserve phases, becomes a dominant systematic uncertainty on g bar (Fukugita et al 1998;Fukugita & Peebles 2004;de Graaff et al 2019;Ghari et al 2019): any upturn in the RAR at the low-acceleration end is suspect since g bar is always implicitly a lower limit.…”

Section: Introductionmentioning

confidence: 99%

Observational constraints on the slope of the radial acceleration relation at low accelerations

Oman,

Brouwer,

Ludlow

et al. 2020

Preprint

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The radial acceleration relation (RAR) locally relates the 'observed' acceleration inferred from the dynamics of a system to the acceleration implied by its baryonic matter distribution. The relation as traced by galaxy rotation curves is one-to-one with remarkably little scatter, implying that the dynamics of a system can be predicted simply by measuring its density profile as traced by e.g. stellar light or gas emission lines. Extending the relation to accelerations below those usually probed by practically observable kinematic tracers is challenging, especially once accounting for faintly emitting baryons, such as the putative warm-hot intergalactic medium, becomes important. We show that in the low-acceleration regime, the (inverted) RAR predicts an unphysical, declining enclosed baryonic mass profile for systems with 'observed' acceleration profiles steeper than g obs ∝ r −1 (corresponding to density profiles steeper than isothermal ρ(r) ∝ r −2 ). If the RAR is tantamount to a natural law, such acceleration profiles cannot exist. We apply this argument to test the compatibility of an extrapolation of the rotation curve-derived RAR to low accelerations with data from galaxy-galaxy weak lensing, dwarf spheroidal galaxy stellar kinematic, and outer Milky Way dynamical measurements, fully independent of the uncertainties inherent in direct measurements of the baryonic matter distribution. In all cases we find that the data weakly favour a break to a steeper low-acceleration slope. Improvements in measurements and modelling of the outer Milky Way, and weak lensing, seem like the most promising path toward stronger constraints on the low-acceleration behaviour of the RAR.

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“…It is thus natural to investigate whether the existence of such scaling could be a hint for modification of gravity at the galactic scales. Modified gravity theories such as Modified Newtonian Dynamics (MOND) [4,5], Weyl Conformal gravity [9,10] and Scalar-Tensor-Vector Gravity (STVG)/Modified Gravity (MOG) [11] have been shown to be in excellent agreement with RAR ( [12] for MOND; [1,13] for Weyl gravity; [14] for MOG). However, [15] found Emergent gravity [16] to be inconsistent with RAR.…”

Section: Introductionmentioning

confidence: 99%

Acceleration relations in the Milky Way as differentiators of modified gravity theories

Islam

Dutta

2020

Phys. Rev. D

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The dynamical mass of galaxies and the Newtonian acceleration generated from the baryons have been found to be strongly correlated. This correlation is known as 'Mass-Discrepancy Acceleration Relation' (MDAR). Further investigations have revealed a tighter relation -'Radial Acceleration Relation' (RAR) -between the observed total acceleration and the (Newtonian) acceleration produced by the baryons. So far modified gravity theories have remained more successful than ΛCDM to explain these relations. However, a recent investigation has pointed out that, when RAR is expressed as a difference between the observed acceleration and the expected Newtonian acceleration due to baryons (which has been called the 'Halo acceleration relation or HAR'), it provides a stronger test for modified gravity theories and dark matter hypothesis. Extending our previous work [1], we present a case study of modified gravity theories, in particular Weyl conformal gravity and Modified Newtonian Dynamics (MOND), using recent inferred acceleration data for the Milky Way. We investigate how well these theories of gravity and the RAR scaling law can explain the current observation.

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The radial acceleration relation and dark baryons in MOND

Cited by 15 publications

References 67 publications

The radial acceleration relation in galaxy clusters

The radial acceleration relation in galaxy clusters

Observational constraints on the slope of the radial acceleration relation at low accelerations

Acceleration relations in the Milky Way as differentiators of modified gravity theories

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