What happens when galactic Dark Matter haloes meet?

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starbrush
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What happens when galactic Dark Matter haloes meet?

Postby starbrush » Thu Oct 12, 2017 3:18 pm

Dark Matter seems not to interact with anything we can detect, or to reveal itself except by gravitational effects.
But is it thought to interact with itself? What might happen when galactic haloes meet - for example our galaxy and M31 in Andromeda? Two pennies, placed about twenty diameters apart, give a rough idea of the current separation, but might their Dark Matter haloes already be interacting?

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Chris Peterson
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Re: What happens when galactic Dark Matter haloes meet?

Postby Chris Peterson » Thu Oct 12, 2017 4:21 pm

starbrush wrote:Dark Matter seems not to interact with anything we can detect, or to reveal itself except by gravitational effects.
But is it thought to interact with itself? What might happen when galactic haloes meet - for example our galaxy and M31 in Andromeda? Two pennies, placed about twenty diameters apart, give a rough idea of the current separation, but might their Dark Matter haloes already be interacting?

There isn't much (or any) evidence that dark matter interacts with itself except through gravitation. When galaxies collide, their dark matter halos do interact, which has been observed.

The halos around the Milky Way and Andromeda are not large enough to have come into contact yet, or for their to be any significant tidal interaction.
Chris

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neufer
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Re: What happens when galactic Dark Matter haloes meet?

Postby neufer » Thu Oct 12, 2017 5:32 pm

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