Modified gravity makes galaxies brighter

Testing Modified Gravity with Motion of Satellites around Galaxies

A modified gravity (MOG) theory, that has been successfully fitted to galaxy rotational velocity data, cluster data, the Bullet Cluster 1E0657-56 and cosmological observations, is fitted to the motion of satellite galaxies around host galaxies at distances 50-400 kpc providing a new sensitive test for MOG. We show that observational data from the Sloan Digital Sky Survey are consistent with MOG...

Testing gravity with motion of satellites around galaxies: Newtonian gravity against Modified Newtonian Dynamics

The motion of satellite galaxies around normal galaxies at distances 50-500 kpc provides a sensitive test for the theories. We study the surface density and the velocities of satellites around isolated red galaxies in the Sloan Digital Sky Survey. We find that the surface number-density of satellites declines with the projected distance as a power law with the slope −1.5− 2. The rms velocities ...

Constraints on modified gravity from Planck 2015: when the health of your theory makes the difference

Does gravity operate between galaxies ?

The redshifts and luminosities of type 1A supernovae are conventionally fitted with the current paradigm, which holds that the galaxies are locally stationary in an expanding metric. The fit fails unless the expansion is accelerating; driven perhaps by ‘dark energy’. Is the recession of the galaxies slowed down by gravity or speeded up by some repulsive force? To shed light on this question the...

Modified gravity and cosmology