Proof roche limit around galaxies exists

https://www.legacysurvey.org//viewer/?ra=170.8186&dec=-8.6684&layer=ls-dr9&zoom=14

This isn’t about the destruction of a satellite, not even a satellite galaxy

This is about what happens when some force, perhaps a fly-by., increases the rotation speed of a mature spiral - probably a spiral-3+ but a spiral with a full halo

The newly faster rotation of the disk moves more stars out past the point where the centrifugal force of orbiting objects (stars in this case) exceed the pull of the core’s gravity

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But that can’t be the whole story, that just pulls some stars out

It doesn’t really address the cleared infield.

As we know, stellar orbits are in a rough equilibrium based on the speed of the object and the mass of the core which grows slowly over time.

If there is a 3-way merger in the local group though, and a runaway core or a large fragment of one was ejected and then caught later by a neighboring many-armed galaxy, it could instantly raise the mass of its core by a very large amount.

The newly heavier core would then draw stars below a new threshold into its mass - clearing a larger infield.

All those new stars packed so tightly are also bound to produce a wave of mergers, novae, etc and dramatically increase the galactic winds which would push things out as well.

All of the above might produce this Hoag’s-like object

Roche limits around galaxies is still being debated as of now.

What are the objects that get stretched / destroyed?

I’m trying and failing to think of examples

Just for objects getting stretched or destroyed (putting Roche limit talk aside for now), stellar streams are formed by galaxies tearing apart clusters. On a smaller scale, any errant things that fly around but more generally clusters are susceptible to this stretching/destruction