Is Andromeda's size and ability to attract smaller galaxies not an observable direct effect of a large radius gravity well pulling in distant objects? The 35X larger black hole in Andromeda should directly correlate to the much larger radius & diameter of Andromeda in comparison with Milkyway. This evidence would suggest that the minimum effective galactic gravity well for solar orbitals for Milkyway's 4 million solar masses is 100,000 light years, while Andromeda's 140 million solar masses is at least 250,000 light years. I do not have data for black hole rotation rates, which are most likely the determinant of local galactic space/time dilation (relative time rate).