Analysis Of Weak Field GR Effects In Galaxies (And MOND Still Works)

The conclusion that gravitomagnetic GR effects don't explain dark matter phenomena has been well established by multiple independent papers including Ciotti (2022). I'll look into what this paper has to say in depth once my taxes, which need to be filed or extended with payment made, are taken care of by the April 18, 2023 deadline.

It has been suggested that the observed flat rotation curves of disk galaxies can be a peculiar effect of General Relativity (GR) rather than evidence for the presence of dark matter (DM) halos in Newtonian gravity. 

In Ciotti (2022) the problem has been quantitatively addressed by using the well known weak-field, low-velocity gravitomagnetic limit of GR, for realistic exponential baryonic (stellar) disks. As expected, the resulting GR and Newtonian rotation curves are indistinguishable, with GR corrections at all radii of the order of v2/c2≈10^−6. 

Here we list some astrophysical problems that must be faced if the existence of DM halos is attributed to a misinterpretation of weak field effects of GR.

Luca Ciotti, "Rotation curves of galaxies in GR" arXiv:2304.06151 (April 12, 2023) (Proceedings of EAS2022, Symposium S3, to be published on Memorie della SAIt).

Another study, meanwhile, has found that the MOND constant threshold for "globular cluster systems is valid for early-type galaxies of all masses and . . . also applies to the red and blue sub-populations of global clusters separately", thus further extending the domain of applicability of this gravitationally based approach to dark matter phenomena.

Meanwhile, a recent attempt to fit mostly Milky Way kinematics to dark matter particle properties concludes that a neutral fermionic dark matter candidate should have a fermion mass in the ∼ 50–350 keV range, which is on the heavy side compared to previous warm dark matter theories.