Q&A WITH A DWARF GALAXY HUNTER

The Euclid space telescope has only just begun its six-year-long mission to map the night sky, but it's already revealed a treasure trove of new galaxies

- Anita Chandran talks to Professor Francine Marleau

What did your team discover?

We discovered around 2,600 low-mass, very low-surface-brightness, faint galaxies from data released by the Euclid space mission. These are historically very hard to find because they're so small and faint, but they're the most numerous galaxies in the Universe. Our dataset was from only 0.4 per cent of the total survey we will eventually get from Euclid, so this was an initial survey of a much larger dataset.

What is Euclid?

Euclid is a space mission that ESA launched in 2023. Its goal is to take images and spectral data in the optical and infrared of around one third of the sky. It does that with fantastic sharpness, because the telescope is in space and responsive to very low brightnesses. One of Euclid's goals is to map the Universe's structure and probe the nature of dark matter and dark energy on the cosmic scale. Because it can see such a wide area, it can give us an idea of how astronomical objects are clustered ona cosmic scale. But it also includes other scientific investigations, like this project, which was to look at the population of what we call dwarf galaxies.