mein projekt

I realised tonight that a few friends probably (or rather, actually) have no idea what my Honours project is about. And then I thought about it some more and figured I'd kill a few birds with one stone, and some future (Higgs? I can't help it…) birds too. I mentioned in a few places that I'm studying Honours at the moment, so it might be worthwhile to elaborate a bit on that and outline my project, though I obviously can't go into detail at this stage since it's not finished yet. And if I told you, I'd have to… you know.

Firstly, Honours is apparently a quite uniquely Australian concept, which serves to fill in the gap between undergraduate and PhD (doctorate). Many countries refer to this time of study as 'Masters', but Australia is different because we also have a Masters stream. While Masters takes two years to complete, Honours is a one-year program with a project. In order to qualify you have to have a certain average grade or above, and I guess in general Honours is regarded as a more challenging or difficult path of choice. I'm not particularly sure why we have both, but we do. It confuses lots of people, from experience.

The Honours project is a research project that you do in a certain field (astrophysics, plasma physics, theoretical physics… etc) on a particular research topic. Generally these topics are laid out in a project list, but I think it is possible to choose from scratch. However, most projects have a rough outline and some fundamental structure behind them, from which students are expected to take whichever path they develop (along with input from their supervisor) to reach the goals or aims of the project - there is a lot of flexibility in that sense. You have around one year (a fair bit less really, especially given the time-eating of coursework) to finish your project. A lot of projects lead on to PhD work, and many people aim to publish a paper shortly after Honours wraps up.

So that's the system, pretty much. Due to matters of national security (jokes, I hope you realise) I won't go into too much detail about my project. I can live in the Bond delusion a little bit longer, I think. In short, for the sake of those with no idea about what I do (hint: nothing to do with black holes or Pluto!), I'll outline the premise.

Most people know we reside in a galaxy, which is one of billions of galaxies in the universe. It's called the Milky Way, and is home to a heckload of stars. The closest link my project has to black holes is this stellar link, but it's tenuous at best. When stars die, there are a few options available to them: black hole, brown dwarf, white dwarf… But what can also happen is a huge (and I mean huge) explosion, as bright as an entire galaxy (see the image below), where the star is literally blown to pieces. This is called a supernova (SN), and happens more regularly than you might think (one estimate is roughly three/century). And when it gets old enough, it crosses the wavy boundary line (~300 years) and becomes a supernova remnant (SNR).

And this is where my project lies. What we know supernovae comes from studies of the Milky Way and other similar galaxies, and this allows us to make predictions of how many supernovae per century we expect. With an average SNR lifetime of around 100,000 years, this also allows us to make predictions of how many SNRs should still be lurking around somewhere in the Galaxy1. So, you can probably confirm for yourself that if we take three/century, there should be around 3,000 SNRs distributed (unevenly!) throughout the Milky Way. Actually, more conservative predictions favour 1,000, which equates to one/century.

Here's the tricky bit: the most comprehensive SNR catalogue2, compounded over the last thirty years, features all of 274 SNRs. That's only 25% of what a fairly conservative estimate predicts! And this most recent catalogue was by no means easy to compile, representing the work of hundreds of physicists all around the world over the last three decades. One of the big questions of contemporary Galactic astrophysics is precisely this, then: where are the missing SNRs?

And that's a question my project, in some small way, hopes to answer. It is widely believed that the current deficiency is due to the limitations of the previous surveys and to selection effects, and that if we keep looking with higher resolution, greater sensitivity and wider fields of view, we'll find them. Suffice to say, lots of people are looking, in different ways. And by different ways, I mean different techniques, different telescopes, different wavelengths/frequencies (depending which regime you are in), different identification methods. It's not an easy problem to resolve, and there may yet be another deeper underlying piece of this puzzle, to be traced out in future.

My project, put simply, is this: find some of the missing SNRs! It's a intra-Galactic treasure hunt, and it takes a fair bit more than just looking up at the sky to solve this one.

Here's hoping that this makes it to the adventures, with a hearty affirmative in the 'treasure found?' section.

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