The Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope has taken an image of the dwarf irregular galaxy PGC 18431.
This image shows the dwarf irregular galaxy PGC 18431. Image credit: ESA /Hubble / NASA.
Our home Milky Way Galaxy is just one of many galaxies. Galaxies clump together in clusters and even huge superclusters.
The Milky Way, for example, is part of a cluster of over 50 galaxies known as the Local Group.
The sphere of space surrounding our Galaxy is known as the Local Volume, a region 35 million light-years in diameter and home to several hundred known galaxies.
PGC 18431, also known as 2MASX J06071970-3412161 or HIPASS J0607-34, is one of these galaxies.
It is a dwarf galaxy located in the constellation Columba, about 31 million light-years away.
The new image from Hubble shows the galaxy smudged across the sky, but it wasn’t imaged purely for its looks.
These observations were gathered in order to probe how Local Volume galaxies cluster together and move around.
Hubble allows astronomers to explore star populations within these moderately distant galaxies in order to get an idea of the galaxy’s composition and, crucially, its distance from us.
Knowing galactic distances enables us to accurately map a galaxy sample in three dimensions, a method key to understanding more about our cosmic neighbors, and to dismiss perspective and line-of-sight illusions.
