http://arxiv.org/abs/2105.14679
We revisit the structure of conformal gravity in the presence of a conformally coupled scale breaking scalar field, and in the static, spherically symmetric case find two classes of exact exterior solutions. In one solution the scalar field has a constant value and in the other solution (due to Brihaye and Verbin, Phys. Rev. D 80, 124048 (2009)) it has a dependence on the radial coordinate, with the two exterior solutions being conformally equivalent. However, the very structure of the solutions requires the presence of singular sources, with the associated sources that are needed in the two cases having different singular structures, to thereby make the interior solutions conformally inequivalent. We show for the radially dependent solution that even if the scalar field does vary macroscopically along particle trajectories, for galaxies this has a negligible effect on galactic rotation orbits. Now since these scalar fields generate particle masses they actually are microscopic not macroscopic and only vary within particle interiors, giving particles an extended, baglike structure. Being internal they anyway have no effect on galactic orbits to begin with. In a recent paper Hobson and Lasenby (arXiv:2103.13451 [gr-qc]) raised the concern that the fitting of conformal gravity to galactic rotation curves had been misapplied and thus called the successful fitting of the theory into question. Here we show that their paper as well as that of Brihaye and Verbin have some technical shortcomings, which leave the good conformal gravity fitting to galactic rotation curves intact.
P. Mannheim
Tue, 1 Jun 21
29/72
Comments: 14 pages, 3 figures
You must be logged in to post a comment.