Dark Galaxy Candidate Nearly Invisible
Astronomers have found what may be the strongest candidate yet for a "dark galaxy," dubbed Candidate Dark Galaxy 2 (CDG-2). This structure contains only a handful of stars and is composed almost entirely of dark matter, making it nearly invisible except for faint emissions and globular clusters. The discovery supports the notion that dark matter dominates galactic formation and structure.
- The discovery of Candidate Dark Galaxy 2 (CDG-2) was made possible by a team of astronomers who first identified a tight grouping of four globular clusters, which can indicate the presence of a faint, otherwise hidden, galaxy. - This nearly invisible galaxy is located about 300 million light-years away in the Perseus galaxy cluster. - Observations from the Hubble Space Telescope, the ESA's Euclid space telescope, and Japan's Subaru telescope were combined to detect a faint glow of stars around the globular clusters, confirming the galaxy's existence. - It is estimated that a staggering 99% of CDG-2's mass is composed of dark matter, making it one of the most dark matter-dominated galaxies ever observed. - The luminosity of CDG-2 is roughly equivalent to a mere one million Suns, and its four known globular clusters account for about 16% of its total visible light. For comparison, our Milky Way galaxy has over 150 globular clusters. - One hypothesis for CDG-2's lack of stars is that gravitational interactions with other galaxies within the dense Perseus cluster stripped away the gas needed for star formation. - The discovery of CDG-2 followed the identification of another candidate, CDG-1, and further observations of CDG-1 are considered imperative as it could be an even more extreme example of a galaxy with hardly any stars outside of its globular clusters. - Another recently discovered dark galaxy candidate, J0613+52, was found accidentally by the Green Bank Telescope and is considered a primordial galaxy, composed of gas from the early universe that has not been enriched by stellar explosions.
