1st Blog Post: Visual Classification of Galaxies

Hello, welcome to the project blog for the visual classification of galaxies in a super-structure project. My name is Jess. Please follow the links if you would like to learn more about me or about the project.

This week, I have classified 591 galaxies (out of 696), although some of these were repeated images. I’ve found that the pace at which I can classify has got progressively faster each day. Hence, I have gone from classifying about 50 galaxies in a day to over 200 over the course of this week, which means the classification will be finished sooner than I had anticipated. Once the classification is finished, the data gathered can be analysed and perhaps you will be able to read about that in next week’s blog post.

For now, I would like to explain the system I have been using to classify galaxies and show you some of the galaxies that I found most interesting.

I classify galaxies according to their shape first- identifying whether they have a disc (a less dense area of stars around a central bright area called a bulge), are elliptical (uniform brightness in an ellipse shape), are point-like or are irregularly shaped. Discs are typical of younger galaxies that are forming stars and often show spiral patterns (which can look very pretty!), whereas ellipses can indicate an older galaxy that is not forming stars any more. I also say whether two galaxies are merging or if a galaxy has multiple bright spots, in which case it is called a clumpy galaxy, and measure its size. I can also choose or reverse the colour scheme so that I can see the galaxy more clearly, or just to prevent my eyes from tiring.

jess_1
This first galaxy is a spiral with an arc-shaped clump at the bottom left. It appears to be pulled towards another galaxy but on further inspection it turns out to not be merging- the shape is interesting though.
jess_2
This galaxy is interesting because it remains ambiguous for now. It looks like it might be merging or could just be clumpy but spectroscopy (analysis of the elements found in the galaxy) couldn’t decide if an interaction was taking place, so this will have to be determined by other methods.

Thanks for reading- see you next time!

Jess

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