Bending Under Pressure: What Lies Beyond a Galaxy
Cosmology tells us that roughly only 5% of matter in the universe is made up of normal atoms and matter that we’re familiar with. However, when astronomers try to take account of the matter they can see inside of galaxies, they find something puzzling – some of it is missing! So, where could it possibly be? It turns out there’s a good chance that it’s not inside of galaxies at all, but completely outside of them in a hard-to-observe gaseous state. When there are thousands of galaxies clustered together, this gaseous medium gets hot enough for us to see it at X-ray wavelengths, but in smaller groups of galaxies (typically 10s of galaxies), it is still difficult to observe and account for. While we can’t see the gas directly, we can see the effect it has on galaxies embedded in it. For example, high energy jets formed by active supermassive black holes at the centers of galaxies are typically very narrow and straight. However, when in galaxy groups, we can see the jets being bent back as the galaxy moves through the gas, similar to how a car’s antenna bends back when you’re driving on the highway. For my thesis work, I am using these peculiar bent jets to learn just how much gas exists in galaxy groups and how it can affect how these galaxies evolve.
Melissa is a 4th year graduate student at the University of Wisconsin-Madison working with Eric Wilcots. Most of her research involves observations of galaxies at radio wavelengths to learn about their environments and how they change and evolve over time. On top of research, She’s also very passionate about teaching, mentoring, and outreach. She thinks it’s important to share science with as many people as possible to help improve science literacy (also because space is cool and she wants to make sure everybody knows it). Every now and then, you can hear her talking about fun astronomy discoveries on Radio Astronomy, a weekly short segment on WORT 89.9FM that airs on Tuesdays! Outside of grad school, she enjoys kayaking, video games, and going on adventures with her 10 year old lab!