Clusters of Galaxies in a Weyl Geometric Approach to Gravity

Abstract

A model for the dark halos of galaxy clusters, based on the Weyl geometric scalar tensor theory of gravity (WST) with a MOND-like approximation, is proposed. It is uniquely determined by the baryonic mass distribution of hot gas and stars. A first heuristic check against empirical data for 19 clusters (2 of which are outliers), taken from the literature, shows encouraging results. Modulo a caveat resulting from different background theories (Einstein gravity plus ΛCDM versus WST), the total mass for 14 of the outlier reduced ensemble of 17 clusters seems to be predicted correctly (in the sense of overlapping 1 σ error intervals).

A scalar field inducing a non-metrical contribution to gravitational acceleration and a compatible add-on to light deflection

“…If the above optimistic approach for estimating the averaged scalar field halo of the galaxies is justified, our model may be able to explain cluster dynamics without additional dark matter. A heuristic check with observational data of 17 + 2 clusters taken [77,78], evaluated like in [59] for a similar, although in its justification problematic, model gave encouraging results. For 15 of the 17 outlier reduced clusters the observational errors and the model spread overlap (for the remaining two a minor extension leads to overlapping).…”

“…This cancelling has been overlooked in[59,60]. The tensor(H ) contains second order derivative terms comparable to (D 2 φ) of the present approach (see below, Eq.…”

“…In [59,60] it has been claimed that a scalar field, nonminimally coupled to the Hilbert action and with the cubic kinetic term L Dφ 3 (but without L D 2 φ ), can already bring new insight for the dark matter/modified gravity problem if is dealt with in framework of Weyl geometric gravity. Due to a flawed heuristic treatment of the weak field approximation, the energy momentum expression of the scalar field resulting from the variation of the non-minimal coupling (here Eq.…”

The Unexpected Resurgence of Weyl Geometry in late 20th-Century Physics

“…This seems to have striking consequences for the dynamics of galaxy clusters. In a heuristic investigation of data from 17(+2) clusters 138 our author found an encouraging agreement of accelerations predicted by the Weyl geometric scalar tensor theory with the corresponding empirical values (Scholz, 2016b). This was done on the basis of the observed baryonic masses alone, without assuming additional unseen, "dark", matter.…”

Corrigendum to “Clusters of Galaxies in a Weyl Geometric Approach to Gravity”

“…

In the article titled "Clusters of Galaxies in a Weyl Geometric Approach to Gravity" [1], there was an error in equation (47) that led to a wrong relation between the acceleration due to the scale connection ( ) and the acceleration arising from the scalar field energy density ( sf ). The correction of (47) has consequences for the model.

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