I should mention, regarding the rain idea I'm studying, that if matter is s=
hot out of a galaxy along the axis of rotation by BH jet activity, and it s=
ubsequenty "rain's" back down onto the galaxy, the NET angular momentum of=
the "rain" would also be zero. It would also be orthogonal to (have angul=
ar momentum vector orthogonal to) the angular momentum of the galaxy.

Thus, rain if it exists, will reduce net angular momentum of a galaxy, shut=
ting down rotation and evolving the galaxy from spiral forms toward EO.

This is possible if the individual particles, stars, gas, dust, rain back d=
own along highly elliptical geometries with long axis coincident with galac=
tic rotation vector, AND, the rain is random with regards to which side of =
the central black hole it falls on. This way, the momentum vectors for eac=
h "particle" are roughly within the disk of the galaxy's rotation, ~normal =
to it's angular rotation vector. But the vector for each particle is diffe=
rent so that there is no net rotation axis.

In a sense, the rain would probably be a bit like a faint bar of stuff that=
thermalization would randomize......the rain would become random like orbi=
ts in a GC, and, the matter of the galaxy with which the interaction took p=
lace would also become more random, more like an elliptical.

So, BH jets, are observed to eject matter. **IF** that matter rains back d=
own, then it should act to evolve the galaxy toward elliptical by some degr=
ee. More rain, more evolution.

Question is, can any observation detect such a rain IF it exists? We see f=
aint extensions. But finding their velocity is harder still and I don't kn=
ow of any observation for the velocity of the faint extended material along=
BH jet axis'.

This mechanism is why the EO to Bar evolution path makes no sense to me. T=
here are only old stars in ellipticals. Barred spirals have newborn stars.=
And most galaxies observed are ellipticals, and they have only old stars.=
EO ought to be the end game it seems to me.

Is it the general expectation that all elliptical galaxies will evolve to b=
arred spirals eventually?

rt