Galaxies are great; full of complexity, rich in variety and very pretty to look at! One way or another all my research is related to galaxies and more specifically to disc galaxies (like our own Milky Way and its nearest neighbour, Andromeda).
Galaxies are pretty tricky to study, astrophysics is unlike most other scientific pursuits in that you cannot actually do experiments! All you can do is take a look at each galaxy from a single perspective and you certainly cannot see how they evolve because the timescales are simply too long.
Fortunately we think we know a few things about what goes into making a galaxy. We know¹;
the laws of gravity
that gas emits and absorbs radiation
that stars form from dense regions of gas
stars output radiation, stellar winds and explode as supernovae
that they are composed of stars, gas (mostly hydrogen and helium) and an invisible kind of matter we call 'dark matter'
By combining these processes we can create computer models of galaxy formation to see how these processes interact and conspire to create these
spiral galaxies. I am interested in how the star forming regions of the galaxy come to be and how they are destroyed by the stars that they
create and by the galactic environment itself. The greatest simulation I have been involved in is the Horizon-5 project, a fly-through of
which is shown below. This zoom back in time shows a huge simulation volume intially with galaxies as they appear today and going back towards
the beginning of time!