How did a lopsided disk of stars form around the supermassive black hole at Andromeda galaxy's core?

Hypothesis presented seems plausible.

I was surprised to learn Andromeda is twice the diameter of Milky Way. I would be curious to know the average spacing between the red group stars he spoke of, my off the top estimate would be .15ly.

Check out Alcyoneus( largest known galaxy)

I don't know what the spacing is however it is noteworthy that the predicted collision is expected to be fairly peaceful,more of a merger than something cataclysmic.

I still can't get over the Milky Way being a barred spiral.

I once went to a spiral bar.
I was pretty dizzy when I left.
Even starry eyed you could say

I remember seeing a news article on this:
chandra.harvard.edu/press/00_releases/press_011400m31.html