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Message started by Cygnus2112 on 03/12/12 at 22:07:38

Title: Galaxy Sim
Post by Cygnus2112 on 03/12/12 at 22:07:38

I am attempting to simulate a barreed spiral galaxy but I'm not sure about the orbital elements. I could probably figure them out on my own after some time, but perhaps someone here has tried a similiar galaxy sim?

I will make a supermassive blackhole at the center, with a nucleus of high-mass objects.
Then I will make 4 arm section, with 2 sections on each side of the nucleus.
2 will have the longitude of ascending node at 0; the other 2 at 180.
and the sections closest to the nucleus will have higher mass than those farthest away.

If anyone has tried something similar, I'd be interested to hear how it turned out, and masses, radii, and mass ratios were used.
Should the proximal sections have more objects than the distals? Should the nucleus have more than an the arms?
(Should the mass ratio be 1:1:1, or 1:2:3, etc..)

Title: Re: Galaxy Sim
Post by frankuitaalst on 03/14/12 at 11:48:32

Good intention Cygnus ,welcome here !
I'm not aware this kind of simulation ever was done here in this forum .
Concerning the setup of the system : unless Tony comes with a magic idea I think you will have to do the setup in several steps :
first create a bunch of identical  masses in 1 direction, then in a direction 90 , then 180 and finally 270 , each ranging from x to y AU's.
then create a new class of ( smaller )masses ,  in each direction , ranging from y to z AU's .
Then going even further with even smaller masses , ranging from z to...z1 AU's ....

So if you want to differentiate into 3 mass populations you'll have to do 3*4 setups in this system ...

Concerning the mass distrubution . There's as far as I know no golden rule for this .

After some googling I've found this (amoning several others )
http://www.physicsforums.com/showthread.php?p=881160
In this model the density falls of as 1/r with distance from the central bulge

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