Milky Way v Andromeda

[mental4astro]

Hi all,

I seem to recall reading somewhere recently of some new thinking about the relationship between the Milky Way and Andromeda. I now cannot remember where, and if this is the new accepted thinking.

Andromeda is larger in apparent size to the MW. But, new observations and maths has show a different set of gravitational influences on each other, and so new trajectories. These different parameters can only be achieved if the mass of each galaxy is closer to being the same rather than the mass of Andromeda being greater than the MW's. This in turn implies that MW must have more dark matter than Andromeda in order to fulfil the apparent mass deficiency from what was originally postulated of the MW.

Is this the current situation?

Regards,

Alex.

[rustigsmed]

Hi Alex,

Maybe something like this?

http://www.scientificamerican.com/article/the-milky-way-s-missing-mass-partially-found/ ?

Russ

[mental4astro]

Thanks for the link, Russell! It helped me find another piece:

http://www.space.com/29270-milky-way-size-larger-than-thought.html

Man, the MW really is a monster... :tasdevil:

[Kunama]

The rippling is possibly the result of the collision with whatever galaxy collided with the MW leaving the remnant galactic core we now know as Omega Centauri....

[blenatca]

Interesting paper on this here - http://arxiv.org/abs/1405.0306
and http://arxiv.org/abs/1405.3662

[ngcles]

Hi All,

There has been much to and fro over the last ten years on the issue of the Milky Way's mass. I believe the preponderance of opinion at the moment favours a Milky Way that is marginally more massive than Andromeda (M31), but more compact. This implies that our galaxy, having less stars than Andromeda, must have a larger dark-matter component and more baryonic matter in the form of star-building raw materials (HI and HII clouds)than Andromeda. Yep, our Milky Way can hold its head up proudly as a super giant barred spiral toward the top of the mass range for that type of galaxy. It is no wimp.

Best,

L.

[mental4astro]

Many thanks for the help and info, folks.

Interesting to see that being located within the disk of the MW, it has obscured a lot of our view of the MW. It is only slowly that with new instruments, computing power, and technology, the full extent of the MW is being revealed. I'm finding this quite fascinating. This is the sort of stuff I just love sharing at outreach nights. Gives novices to astro a very new appreciation of what's up there.

The MW now being considered bigger than Andromeda in mass, corrr blimey! Big sucker alright. Thanks Les.