Skywatcher Giuseppe Donatiello noticed an ultra-faint dwarf galaxy, presently named Pegasus V, in archival data from the U.S. Department of Energy camera designed to track dark energy. Fascinated astronomers who heard about these observations then studied the region through a bigger Hawaiian telescope, known as Gemini North. Scientists now believe that Pegasus V might be a “fossil” of the first galaxies, loaded with ancient stars.
“This discovery marks the first time a galaxy this faint has been found around the Andromeda Galaxy using an astronomical survey that wasn’t specifically designed for the task,” Michelle Collins, an astronomer at the University of Surrey in the United Kingdom who directed the new research, declared in a statement from the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab).
The galaxy was first observed in the data collected by the Víctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in Chile. Donatiello was taking part in an inquiry for Andromeda dwarf galaxies performed by David Martinez-Delgado from the Instituto de Astrofísica de Andalucía, Spain when he spotted Perseus V
Discovering such an object is important because astronomers expect several faint galaxies to exist but have identified very few of them. Scientists aren’t sure why that discovery gap for these faint, fossilized galaxies might prevail, although their soft glow makes them difficult to spot even by professionals.
However, if future searches turn up relatively empty, astronomy may be facing a reckoning. “If there are truly fewer faint galaxies than predicted, this would imply a serious problem with astronomers’ understanding of cosmology and dark matter,” NOIRLab announced.