MADRID, Spain – Astrophysicists in Spain have discovered a hitherto unknown dwarf galaxy, named Nube, which is the largest and most diffuse galaxy recorded to date, defying existing astrophysical models. Led by Mireia Montes of the Instituto de Astrofísica de Canarias (IAC), the group’s study, published in the journal Astronomy & Astrophysics, used data collected from the Gran Telescopio Canarias (GTC) and the Green Bank Radiotelescope (GBT).
Named by the 5-year-old daughter of one of the researchers, Nube – Spanish for “cloud” – was identified because of its nearly invisible, spread-out appearance. The galaxy’s extreme characteristics set it apart: Nube is estimated to be a dwarf galaxy ten times dimmer than others of its type, yet also ten times more extended than objects with a similar number of stars. For reference, Nube is only one third of the size of the Milky Way, but has a mass similar to that of the Small Magellanic Cloud.
The discovery has puzzled astronomers, including Montes, who expressed surprise at the lack of understanding of how a galaxy with such extreme characteristics could exist. With its density of stars varying very little throughout the object, Nube is remarkably faint, and its existence has raised major challenges in the field of astrophysics. The current dark matter model is unable to account for the “extreme” characteristics of Nube, posing a significant challenge to existing cosmological simulations.
The research team has worked to determine the exact distance of Nube, estimating it to be 300 million light years away, although further observations with various telescopes should clarify this distance. The finding of this galaxy, and others with similar properties, could offer new clues to enhance our understanding of the universe, according to Montes. Ignacio Trujillo, a co-author of the study, finds the unusual properties of Nube potentially indicative of an extremely small mass of particles that make up dark matter, which would revolutionize our understanding of the universe.