Could we be making a mistake about the distribution for "dark matter" in galaxies?

The descriptions I read about the distribution of "dark matter" in galaxies seems to show it as somewhat hollow, in a "halo" instead of a spherical blob with greatest density at the center.

I understand that this is inferred from the apparent lack of sufficient gravity from the detected luminous matter to explain the orbital velocities of stars around the galaxy center, as a function of their distance from the center. So, this distribution seems to be calculated on the basis of (enough matter) minus (visible matter).

And, that would make sense so long as the "dark" matter is normal matter that we just can't see in the dark.

However, once we postulate that "dark matter" is some other form of matter that does not interact with regular matter, except to be attracted to it (and itself) by gravity, this distribution does not seem to make sense any more.

For instance, why would the dark matter not be most dense where the regular matter is most dense? And why would dark matter not become dense blobs of its own accord, just like regular matter clumps to form stars, planets, etc.?

It is hard for me to come up with some sort of internal dark matter to dark matter interactions that would produce the "halo" result.

However, it does seem plausible that we could be calculating the combined gravitational effects of both regular and dark matter where we see luminous regular matter, and thus are over-estimating the actual mass of the regular matter. So, when we subtract that over-estimated mass of the regular matter to infer the remaining mass of the dark matter, we would be leaving a "halo" where we don't see so much luminous matter.

Thoughts?
 

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My understanding is that dark matter was introduced as a fudge factor. Originally known as "missing mass" I think it was upgraded to "dark matter" as this sounds less like a fudge.
A rose by any other name would small as sweet
In this case something sounds better if you give it a sweeter smelling name.

Originally known as the “missing mass,” dark matter's existence was first inferred by Swiss American astronomer Fritz Zwicky, who in 1933 discovered that the mass of all the stars in the Coma cluster of galaxies provided only about 1 percent of the mass needed to keep the galaxies from escaping the cluster's ...

dark matter | Definition, Discovery, Distribution, & Facts

Cat :)


 
The descriptions I read about the distribution of "dark matter" in galaxies seems to show it as somewhat hollow, in a "halo" instead of a spherical blob with greatest density at the center.

I understand that this is inferred from the apparent lack of sufficient gravity from the detected luminous matter to explain the orbital velocities of stars around the galaxy center, as a function of their distance from the center. So, this distribution seems to be calculated on the basis of (enough matter) minus (visible matter).

And, that would make sense so long as the "dark" matter is normal matter that we just can't see in the dark.

However, once we postulate that "dark matter" is some other form of matter that does not interact with regular matter, except to be attracted to it (and itself) by gravity, this distribution does not seem to make sense any more.

For instance, why would the dark matter not be most dense where the regular matter is most dense?
It’s my understanding that it does. The central area of a galaxy typically has a larger distribution of DM.

And why would dark matter not become dense blobs of its own accord, just like regular matter clumps to form stars, planets, etc.?
Indeed. There seems to be no evidence of any high density DM pockets, AFAIK.
 

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