Identikit 2: an Algorithm for Reconstructing Galactic Collisions

Joshua Barnes (ifa)

 abstract:

An accurate dynamical model of a collision between two disk galaxies,
constrained by both morphological and kinematic data, can yield a wealth
of information.  Such models can illuminate the present 3-D (or even 6-D!)
structure of the galaxies, establish a time-line for their encounter,
reveal their pre-encounter morphology, and predict the nature of the
remnant produced by the collision.  At present, models are constructed by
tedious trial-and-error search of a large and complex parameter space.  I
will describe and demonstrate a fast algorithm which can backtrack from
the current kinematic structure of tidal features to recover the initial
orientations of the progenitor disks.  I will then show how this algorithm
can be extended to recover the viewing direction and ultimately the other
parameters necessary to describe galactic collisions