In February of 2018 I was invited to give a presentation at the inaugural STEM Festival at the Presidio School in Tucson about my experiences as a scientist.
When most people think about astronomy they imagine someone sitting at a telescope all night, looking at the stars, and recording everything that they see. That isn’t what I do.
Modern astrophysics do more than just observe stars, galaxies, and planets. In fact, most astrophysicists spend way more time in front of a computer than looking through an eyepiece of a telescope. And with the giant, complicated telescopes used throughout the world today (and up in space!), even when we take data with a telescope we still use a computer to control the telescope.
One major theory of how galaxies grow to as big as they are today is by eating up smaller galaxies that get too close. These eaten up smaller galaxies can leave - almost a scar: an over-crowding of stars that eventually gets smoothed out as the bigger galaxy continues to spin. Kind of like when you put a drop of food coloring in liquid and start to stir: at first you can see the color distinctly, but then it mixes in.
When figuring out a galaxy’s formation history, one challenge is finding these scars. But there are these neat little objects that I use to trace them.
I study the galaxy Centaurus A using objects called globular clusters. These are old, dense, groups of stars that all formed at the same time, and so all have the same properties. Globular clusters are found in almost all galaxies, and all the globular clusters in a specific galaxy will have similar properties, like the amount of metal they have and how fast they are moving. This is useful because if you see a line of them that all have the same speed and elements, then they must have all originated in the same little galaxy that got eaten up by the bigger one!
Finding globular clusters in another galaxy is hard to do by just looking, so I create and run computer codes to help me.