According to Universe Today , the Nube galaxy is so faint that the famous Sloan Deep Sky Survey (SDSS) missed it. However, scientists got lucky when another survey program called the IAC Stripe82 Legacy Project accidentally saw it, an almost transparent object.
A research team led by Dr. Mireia Montes from the Institute of Astrophysics of Canarias (IAC - Spain) analyzed and confirmed that Nube is mainly made of dark matter.
The Nube galaxy is marked by a solid black square in the overall view, only faintly visible in more detailed observations (Image: Montes et al)
This "ghost galaxy" is a "nearly dark" dwarf galaxy, about the same mass as the Small Magellanic Cloud, and is one of the satellite galaxies of the Milky Way galaxy to which our planet belongs.
The results come from additional observations using the Green Bank Telescope (located in the US), showing the "ghost galaxy" is about 350 million light-years away.
It is an extremely diffuse galaxy, 26 billion times more massive than the Sun but with a total stellar mass of only 390 million times that of the Sun, suggesting something dark and invisible is occupying it.
That invisible thing is dark matter, a hypothetical substance that is believed to make up most of the universe, even surrounding Earth, but which we cannot see or feel.
Half of Nube's mass is spread out over 22,000 light-years of space and is the largest ultradiffuse galaxy known to scientists.
According to the authors, studying the "ghost galaxy" Nube will be a great opportunity for scientists to answer questions about dark matter.
At the same time, it gives hope that there are many more dwarf galaxies like this "ghost galaxy", we just haven't noticed them, haven't seen them because they are too dim and almost transparent like a ghost.
(Source: Lao Dong Newspaper)
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