A diamond in the rough

Squint or you’ll miss it! At the very centre of this image, taken with the VIMOS instrument attached to ESO’s Very Large Telescope (VLT), you can just about see the faint and fuzzy blue form of a distant galaxy known as the Sagittarius Dwarf Irregular Galaxy.

Discovered in 1977 with the ESO 1-metre Schmidt telescope, situated at ESO’s La Silla observatory, the irregularly shaped — hence the name — dwarf galaxy is approximately 3 million light-years away in the constellation of Sagittarius (The Archer). It is the most distant member of the Local Group of galaxies, of which the Milky Way is a member.

Unlike normal galaxies, dwarf galaxies are typically smaller and host a relatively small number of stars. Gravitational tugs from nearby galaxies can often distort the spherical and disc-like shapes of these fragile galaxies — this very process may be responsible for the slightly rectangular shape of this particular dwarf galaxy.

Acknowledgement: M. Bellazzini et al.