I can't believe I didn't think of this as a subject earlier, I did LOTS of physics in my astronomical imaging internship!
Okay, well, in reality I more looked at images and programs and readings, I didn't actually DO the physics, but there's a lot of physics behind what I did.
My internship was focused on assisting with research around the stellar phase called planetary nebula. This is a post-red-giant phase of smaller stars. The majority of the gases within the star have been burned up or converted through fusion to different elements. In the planetary nebula phase, the outer layers of the star are now composed of ionized gasses, and the core becomes visible. Planetary nebula come in many different shapes, and the theories behind why they form some of the more obscure shapes is still hotly debated, though it is widely agree that interstellar winds create the basic shapes.
I asked one day what an interstellar wind actually was, and received a lecture that resulted in this whiteboard:
Mind you, many things have been erased and written over on this board to explain, and the lecture took at LEAST an hour as well as numerous pages of notes. So I will not be explaining interstellar winds, mostly because its a lengthy explanation and marginally because I don't remember most of it.
The most relevant physics to what I was doing had to do with the ionized gases that surround the planetary nebula. As both basic chemistry and physics teaches us, excited atoms emit light. The gas surrounding the stars in the planetary nebular phase indeed emit a LOT of light, though often times this light is not emitted in the visible spectrum nor even in only one spectra. The emitted light comes in various wavelengths and therefore on various areas of the spectrum (visible, infrared, ultraviolet ect).
To capture images of the emitted light with the most possible information, there are various telescopes and sattelites that take images on different levels of the spectrum (ie Galex sattelite takes xray images). Different spectral images are also useful because different levels of the spectrum correspond to different heats, which help astronomers figure out what is going on in the stars. With all of this in mind, astronomers can use wavelengths to figure out distances, numerous spectral images to deduce shapes, and emissions to figure out the temperature of things happening in space.
Knowing that different things are emitted in numerous levels of the spectrum, my job was usually to gather images from different wavelengths to either see if there was any emission to begin with or to compare emissions we already knew were there. Physics plays a HUGE part in asrtronomy, since we have to use what we know to figure out things that we can do nothing more than observe from a great distance away. You can't exactly take a sample of a nebular gas (even if you found a way to handle the temperatures), so we have to use our knowledge of physics to figure out the mysteries of space.
(the attached images are xray farthest left, and 3 different infrared wavelengths next to that)