Galaxy cluster masses without non-baryonic dark matter

• Published in: Monthly notices of the Royal Astronomical Society Vol. 367; no. 2; pp. 527 - 540
• Main Authors: Brownstein, J. R., Moffat, J. W.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.04.2006; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; Dark matter; Earth, ocean, space; Exact sciences and technology; galaxies: clusters: general; galaxies: kinematics and dynamics; gravitation; Stars & galaxies; X-ray astronomy; X-rays: galaxies: clusters; galaxies: clusters: general; galaxies: kinematics and dynamics; gravitation; X-rays: galaxies: clusters; dark matter; X ray cluster of galaxies; Gravitation; X ray observation; Rotation curve; Mass to light ratio; Mass distribution; M stars; Galaxy clusters; Massive field; Phenomenological model; Dark matter; Dynamics; Dwarf galaxies; Intracluster matter; Surface brightness; Kinematics; Dynamic model; Gravity
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2006.09996.x

We apply the modified acceleration law obtained from Einstein gravity coupled to a massive skew symmetric field, Fμνλ, to the problem of explaining X-ray galaxy cluster masses without exotic dark matter. Utilizing X-ray observations to fit the gas mass profile and temperature profile of the hot intracluster medium (ICM) with King ‘β-models’, we show that the dynamical masses of the galaxy clusters resulting from our modified acceleration law fit the cluster gas masses for our sample of 106 clusters without the need of introducing a non-baryonic dark matter component. We are further able to show for our sample of 106 clusters that the distribution of gas in the ICM as a function of radial distance is well fitted by the dynamical mass distribution arising from our modified acceleration law without any additional dark matter component. In a previous work, we applied this theory to galaxy rotation curves and demonstrated good fits to our sample of 101 low surface brightness, high surface brightness and dwarf galaxies including 58 galaxies that were fitted photometrically with the single-parameter mass-to-light ratio (M/L)stars. The results obtained there were qualitatively similar to those obtained using Milgrom's phenomenological Modified Newtonian Dynamics (MOND) model, although the determined galaxy masses were quantitatively different, and MOND does not show a return to Keplerian behaviour at extragalactic distances. The results obtained here are compared to those obtained using Milgrom's phenomenological MOND model which does not fit the X-ray galaxy cluster masses unless an auxiliary dark matter component is included.