Nube is among the most diffuse galaxies discovered. (Image Credit: GTC/Mireia Montes).
Astronomers have discovered a galaxy in an apparently empty patch of the sky that had been missed by galaxy surveys. The galaxy, named Nube, which is Spanish for ‘cloud’ is an extremely diffused one, with a small number of stars spread out over a large region of space. The dwarf galaxy is about ten times fainter than other dwarf galaxies, and is also ten times more extended. The existence of the galaxy was confirmed using multiple ground and space based observatories. The faintness makes it difficult to accurately estimate the distance to the galaxy, but astronomers estimate that Nube is at a distance of about 300 million lightyears.
The Nube galaxy as imaged by different telescopes. (Image Credit: SDSS/GTC/IAC).
In most galaxies, including the Milky Way, the density of stars increases towards the core, or the central regions. The density of stars falls off rapidly moving away from the centre. Nube is unusual in the sense that the galaxy appears to have a uniform distribution of stars, with very little variations in density. Cosmological simulations cannot produce a galaxy similar to Nube, suggesting that the current scientific understanding of the universe is incomplete. The galaxy cannot be produced in simulations using different theoretical models.
A combined monochrome and colour image of Nube, to isolate the background. (Image Credit: GTC/Mireia Montes).
Whenever such a novel object is discovered for the first time in astronomy, it paves the way for the discover of additional, similar objects. The discovery of additional similar objects can help fine tune the theoretical cosmological models, improving our understanding of the universe. A paper describing the findings has been published in Astronomy & Astrophysics. Second author of the paper Ignacio Trujillo says, “One possibility which is attractive, is that the unusual properties of Nube are showing us that the particles which make up dark matter have an extremely small mass. If this hypothesis is confirmed, it would be one of the most beautiful demonstration of nature, unifying the world of the smallest with that of the largest.”
Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
