Clusters of galaxies with modified Newtonian dynamics

By R. Sanders. 2002

176 citations recorded by the source corpus.

I consider X-ray emitting clusters of galaxies in the context of modified Newtonian dynamics (MOND). Self-gravitating isothermal gas spheres are not good representations of rich clusters; the X-ray luminosity at a given temperature is typically an order of magnitude larger than observed, and the predicted X-ray surface brightness distribution is not well-matched by the standard ‘β-model’ fits to the observations. Pure gas spheres with a density distribution described by a β-model also fail because, with MOND, these objects are far from isothermal and again overluminous. These problems may be resolved by adding an additional dark mass component in the central regions, here modelled by a constant density sphere contained within two core radii and having a mass typically of one to two times the total cluster mass in the gas. With this additional component, the observed luminosity–temperature relation for clusters of galaxies is reproduced, and the typical mass discrepancy in actual clusters is three to four times smaller than implied by Newtonian dynamics. Thus, while MOND significantly reduces the mass of the dark component in clusters it does not remove it completely. I speculate on the nature of the dark component and argue that neutrinos, with mass near the experimental upper limit are a possible candidate.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/646784384b965f562ed73472130d910abb2d9de3

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Citations in the corpus

Galaxy cluster masses without non-baryonic dark matter (2005, methodology): “Meanwhile, both the MOND ‘convergent mass’ and the Newtonian dynamic mass show a discrepancy with the ICM gas mass (Sanders 2003).”
Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions (2011, background): “Figure 39: The baryonic mass–X-ray temperature relation for rich clusters (gray triangles [359, 389]) and groups of galaxies (green triangles [12]).”
History of dark matter (2018, unknown): “If the three known species of neutrinos were as heavy as mν ∼ 1–2 eV (near the upper limits from beta decay experiments), it has been suggested that they might be able to account for this discrepancy, essentially acting as dark matter in clusters (Sanders, 2003, 2007; Angus et al., 2007).”
Weak-Lensing Mass Reconstruction of the Interacting Cluster 1E 0657–558: Direct Evidence for the Existence of Dark Matter (2003, background): “O-0332 Electronic address: dclowe@as.arizona.edu 2 currently at Steward Observatory, University of Arizona ter beyond the observed baryons and a small neutrino mass (Sanders 2003).”
A tensor—vector—scalar framework for modified dynamics and cosmic dark matter (2005, background): “This is a possible solution to the problem of the remaining mass discrepancy in clusters in the context of MOND (Sanders 2003).”
The Mass Discrepancy-Acceleration Relation: Disk Mass and the Dark Matter Distribution (2004, background): “…of axis-symmetry: one should not attempt to apply the assumption of circular motion to objects with grossly asymmetric rotation curves. clusters of galaxies, is less clear (Aguirre, Schaye, & Quataert 2001; Sanders 2003), so the discussion here is restricted to rotationally supported disk galaxies.”