Astronomy Seminar
| Date/Time: | Friday, 23 Mar 2018 from 4:10 pm to 5:10 pm |
|---|---|
| Location: | A401 Zaffarano Hall |
| Cost: | Free |
| Contact: | Steve Kawaler |
| Phone: | 515-294-9728 |
| Channel: | College of Liberal Arts and Sciences |
| Categories: | Lectures |
| Actions: | Download iCal/vCal | Email Reminder |
Knowledge of how galaxies form and evolve is vital to understanding the universe as a whole; they are the fundamental building blocks of the universe's large-scale structure and share a common structure of their own - an exponential surface density profile in their disks. One major interaction between these two scales is the phenomenon of infalling matter - such as dwarf galaxies derived from cosmological galaxy filaments - which becomes bound into orbit around a galactic disk. The result of this process is a number of satellite bodies orbiting the central galaxy in a fairly narrow band set at an angle to the disk. This configuration has been observed not only around our own galaxy and Andromeda, but also around Centaurus A as shown in the 2018 paper by Muller et al. In order to investigate the effects of gravitational influence by such extragalactic bodies on the evolution of galactic disks, I adapted a MATLAB point-scattering simulation code developed by Dr. Curtis Struck and Dr. Bruce Elmegreen. The code, originally designed to simulate the effects of disk-bound clumps of matter, places non-interacting star particles in a galactic gravitational potential and disturbs them with gravitationally attractive perturbing bodies. I modified the code to create fully 3-dimensional extragalactic orbits constrained in a band structure at an angle from the disk and ran the simulation out to 2Gyr with disturber masses ranging from 3.86x10^7 to 3 .86x10^9 M_sun. I found that large disturber masses produced exponential disk surface density profiles but resulted in significant vertical evolution, effectively blowing up the disk. This is intriguing, as it may give insight into the formation of S0 galaxies. Less massive bodies drove neither vertical evolution nor the formation of an exponential profile. However, intermediate masses able to contribute to surface density evolution without blowing up the disk appear to exist.