Gemini North telescope reveals a relic of the earliest galaxies.
A unique ultrafaint dwarf galaxy has been discovered on the outer edge of the Andromeda galaxy, thanks to the astute eyes of an amateur astronomer examining archival data processed by NSF’s NOIRLabs Community Science and Data Center.
The dwarf galaxy Pegasus V contained very few heavier elements and is likely a fossil of the first galaxies in follow-up observations by professional astronomers with the International Gemini Observatory, a program of NSF’s NOIRLab. An unusual ultrafaint dwarf galaxy has been discovered on the outskirts of the Andromeda galaxy with the help of multiple facilities at NSF’s NOIRLab.
Faint stars in Pegasus V were discovered in subsequent deeper observations by astronomers using the larger 8.1-metre Gemini North telescope with the GMOS instrument, confirming that it is an ultrafaint dwarf galaxy on the outskirts of the Andromeda galaxy.
Gemini North in Hawaii is half of the International Gemini Observatory. The observations with Gemini showed that the galaxy appears to be extremely poor in heavier elements compared to similar dwarf galaxies, meaning it is very old and likely a fossil of the first galaxies in the universe.
“We have found an extremely faint galaxy whose stars formed very early in the history of the Universe,” commented Michelle Collins, an astronomer at the University of Surrey, UK, and lead author of the paper announcing the discovery. This discovery marks the first time such a faint galaxy has been found around the Andromeda galaxy using an astronomical survey not specifically designed for the task.”
The faintest galaxies are thought to be fossils of the very first galaxies to form, and these galactic relics hold clues to the formation of the earliest stars. While astronomers think the Universe is teeming with faint galaxies like Pegasus V, they haven’t spotted nearly as many as their theories predict.