This cartoon is part of the DES Y3 #Darkbites social media series. It was drawn to illustrate the paper led by Anna Porredon (website, twitter), titled “Dark Energy Survey Year 3 Results: Optimizing the Lens Sample in Combined Galaxy Clustering and Galaxy-Galaxy Lensing Analysis.” (arXiv:2011.03411)

alt="Illustration of a photoroptor (the machine used to measure prescriptions during eye exams) pointed at a vision test chart with pictures of galaxies on it instead of letters."

The post’s associated text was:

We can learn about the distribution of matter in the Universe by studying the relationship between how gravitational lensing distorts the images of distant galaxies, and the positions of galaxies closer to us which cause that lensing.

Just like you need the right glasses prescription to see clearly, choosing those lens galaxies carefully allows us to get as much information as possible out of our analysis

This paper explores how to pick lens galaxies to optimize the amount of information they provide:

Here’s a link to the post. The twitter thread of the Y3 Darkbites posts begins here. The cartoons also being shared on the DES facebook and instagram pages.