Dark Matter and Galaxy size

[J.C.MacSwell]

Just a question on the general trend of % of of mass in galaxies being DM relative to there size.

 

Do the larger galaxies tend to have more (as a percentage) than smaller galaxies?

 

I tried a search but, at least with the keywords I used, I found no answer.

[krash661]

it is said, dark matter is what holds galaxies in place.

[David Levy]

Dark Matter –

 

When the science doesn't have a logical answerת it's the time for DM…

[krash661]

Dark Matter –

 

When the science doesn't have a logical answerת it's the time for DM…

funny,

logically,

dark matter exist.

Edited June 29, 2013 by krash661

[EdEarl]

Dark Matter –

 

When the science doesn't have a logical answerת it's the time for DM…

Before neutrinos were discovered, a similar misnomer "neutron" was proposed by Wolfgang Pauli until James Chadwick discovered the current neutron particle, and Enrico Fermi developed who the theory of beta decay and changed the name to neutrino.

 

People like to have names for things, even if they do not understand them (DM) or do not exist (genie).

Edited June 29, 2013 by EdEarl

[Archimedes]

I read that dwarf galaxies actually contain higher proportions of dark matter than larger galaxies, (It is important to remember that proportion is not the same as amount). From that, it can be said that smaller galaxies would contain a higher percentage of dark matter than larger galaxies, but this observation could be flawed, and is open to interpretation.

 

-Arch

Edited July 4, 2013 by Archimedes

[Widdekind]

so, bigger galaxies (tend to) generate bigger (& brighter) stars, so increasing their ratio of Light-per-Mass, et vice versa (?)

I read that dwarf galaxies actually contain higher proportions of dark matter than larger galaxies, (It is important to remember that proportion is not the same as amount). From that, it can be said that smaller galaxies would contain a higher percentage of dark matter than larger galaxies, but this observation could be flawed, and is open to interpretation.

 

-Arch

[swansont]

so, bigger galaxies (tend to) generate bigger (& brighter) stars, so increasing their ratio of Light-per-Mass, et vice versa (?)

 

!

Moderator Note

The thread is about dark matter. Please stay on-topic.

[Royston]

Just a question on the general trend of % of of mass in galaxies being DM relative to there size.

 

Do the larger galaxies tend to have more (as a percentage) than smaller galaxies?

 

I tried a search but, at least with the keywords I used, I found no answer.

 

This probably won't help too much, but on the larger scale (i.e dark matter halos in which numerous evolving galaxies can be contained) dark matter evolution can be approximated using the Press-Schechter model and N-body simulations. N-body simulations can be used to track the behaviour of DM halos. Combining N-body simulations with numerical models you can predict certain properties of galaxies, and these are called semi-analytic models. This is more for galaxy evolution, but clearly there's a link to DM distribution and the subsequent properties of a galaxy. This is very new work, and different models require different assumptions. This may give you a starting point to investigate though. Note, that I studied cosmology some time ago, so I'm not sure on the current consensus.

 

There was work carried out by Eduardo Battaner and his team, http://www.alphagalileo.org/ViewItem.aspx?ItemId=58466&CultureCode=en which attempts to resolve what you're asking, but I'm pretty certain it's not accessible (meaning I'm not going to pay for it). But, if you dig around you may find something.

 

I read that dwarf galaxies actually contain higher proportions of dark matter than larger galaxies, (It is important to remember that proportion is not the same as amount). From that, it can be said that smaller galaxies would contain a higher percentage of dark matter than larger galaxies, but this observation could be flawed, and is open to interpretation.

 

-Arch

 

Do you have a link ?

Edited July 4, 2013 by Royston

[Archimedes]

 

Do you have a link ?

I will search for it. It was a while back that I read that. I'll look it up though.

 

---edit---

Here's a link to a page that talks about dwarf galaxies and dark matter: http://www.cosmotography.com/images/dwarf_galaxy_dark_matter.html

 

-Arch

Edited July 4, 2013 by Archimedes