Abstract
The MOdified Gravity (MOG) theory of J. Moffat assumes a massive vector particle which causes a repulsive contribution to the tensor gravitation. For the galaxy cluster A1689 new data for the X-ray gas and the strong lensing properties are presented. Fits to MOG are possible by adjusting the galaxy density profile. However, this appears to work as an effective dark matter component, posing a serious problem for MOG. New gas and strong lensing data for the cluster A1835 support these conclusions and point at a tendency of the gas-alone to overestimate the lensing effects in MOG theory.
Highlights
With the ongoing no-show of the WIMP and the axion, and the natural dark matter candidate, the neutrino, long ruled out (but not given up, see e.g. Nieuwenhuizen (2016)), the dark matter riddle is ripe for reconsideration
Within the often employed spherical approximation, the investigation reveals that Modified Newtonian Dynamics (MOND), EG1, MOdified Gravity (MOG) and f (R) theories fail to give proper account of the lensing data; by default this applies to EG2
We have presented new data sets for the X-ray gas density and strong lensing effects of the well studied cluster A1689 and the investigated cluster A1835
Summary
With the ongoing no-show of the WIMP and the axion, and the natural dark matter candidate, the neutrino, long ruled out (but not given up, see e.g. Nieuwenhuizen (2016)), the dark matter riddle is ripe for reconsideration. In Nieuwenhuizen (2017) one of us investigates whether these theories achieve to explain lensing properties of a well documented galaxy cluster, Abell 1689 (shortly: A1689). It stands out since it is large, heavy and probably quite relaxed. Good data exist for the X-ray gas and its strong and weak lensing properties (Morandi et al 2012a). Within the often employed spherical approximation, the investigation reveals that MOND, EG1, MOG and f (R) theories fail to give proper account of the lensing data; by default this applies to EG2. We present new gas and strong lensing data for a second, well relaxed cluster, A1835, and analyse them in a similar fashion.
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