Can dark matter density be inferred by black hole mass growth?

[repoman]

Dark matter passes though everytging, but I assume it can't pass through a black hole.

So is dark matter just too sparse around black holes to make any observations of mass anomalies from models because of DM hoovering?

One thing is that DM won't be caught up in accretion disks via friction and heat release like baryonic matter which is how black grow mostly grow except for big mergers.

 

[skepticalbip]

never mind

 

[repoman]

On a larger scale could you say that regardless of whatever DM-DM self interaction and therefore frictional dissipation (as well and DM-BM baryonic matter interaction) that there is something more subtle happening.

If there is DM and BM in the same region then the DM's gravity effects (any gravity source would do it) will be transferred into BM frictional losses and then the BM and DM will become closer.

Just an idea.

Also saw a snippet about the Bullet Cluster and how it seems to put some bounds and DM self interaction cross section, but have not looked deeply into it yet.

I hope that there can be more examples like the Bullet Cluter found so that this can be further pinned down.

 

[Shadowy Man]

I don’t know the dark matter densities off the top of my head but my feeling is that it is very low. Also it is so sparse that at small scales it is likely just a background offset to the gravitational potential and wouldn’t do much of anything to your baryonic matter.

But this is not my area of expertise.