Fitting interacting galaxies

[panstarrs]

Hi, I'm a new user of Bbarolo. There is an example of 3D fit of a galaxy on the website, but I didn't see an example of fitting, e.g. two interacting galaxies. I wonder if Bbarolo has the ability of 3D fitting two mergering/interacting galaxies ? If not, could you recommend any tools that may do such a fitting ? I find the HI interacting galaxies in my data cube are close and hard to be separated visually, thanks.

[editeodoro]

Hello, it depends a bit on how much the kinematics of the galaxies is disturbed. If it is a minor merger and the main galaxy isn't too much messed up, then you can definitely give it a try.

But if it is a strong interaction, like a major merger, there is just no hope of studying/reproducing the kinematics with the simple axisymmetric models that basically all kinematic codes use (and also it does not make much sense doing it). In cases like these, if you're interested in studying the merging process, you will be needing full hydrodynamical or N-body simulations to try to reproduce the very complex merger dynamics.

Cheers, Enrico

[panstarrs]

Hi @editeodoro thanks for the quick response. I think it's probably a minor merger in my case, so I'll give it try. I have a follow up question in this regard. Should I carefully cut the cube into two halves such that only one galaxy is present in each half cube in order to make Bbarolo work ? If yes, I'm not sure how to draw a line to cut it. Maybe first look at the moment0 map, then separate the two galaxies as well as possible ? thanks.

[editeodoro]

It's difficult to give you advice without seeing the data! You may be able to just fit the half of each galaxy that is less affected by the merging, without any a-priori cut. If you send me your cube by email, I will take a look and see if I have any good idea about it. Enrico

[panstarrs]

Thanks. I'll try to do this and see if it works, and let you know if it doesn't :), thanks a lot!