stargazer may have just stumbled across a specter coltsfoot hiding in plain slew — a belittled , starless , fast - propel cloud of gas that checks all the boxes for what ’s known as a “ dark galaxy . ” And if the breakthrough holds up , it could help secure one of cosmology ’s most puzzling golf hole : the mysterious “ wanting satellite ” job .
The squad ’s research , publishedtoday in Science Advances , describes AC G185.0–11.5 , a compact hydrogen swarm tucked inside a larger high-pitched - velocity cloud ( HVC ) have sex as AC - I. The swarm was spotted by an international research team using China ’s immense FAST wireless telescope . While HVCs are known to zoom along around at speeds beyond that of our whitish Way ’s rotation , most are comparatively featureless accelerator pedal blob . But the recently distinguish gasolene swarm is unlike : it spins .
FAST ’s radical - sensitive observation revealed a clear rotational pattern in the swarm , whose gas is arranged in a disk form — the sort of structure you ’d expect from a dwarf galaxy . But something ’s amiss : there ’s no sign of stars in the cloud , and no molecular flatulency ( the usual star - shape clobber ) to be found . AC G185.0–11.5 is apparently constituted of just H gun , swirling in infinite , with nothing within it lighting it up . Ergo , a dark wandflower .
The Milky Way above ESO’s Paranal Observatory.Photo: ESO/P. Horálek
Using astronomical motion equations and a cosmic yard measure call the Tully - Fisher relation , the team estimated the cloud ’s length from Earth : about 278,000 light - years . That puts the swarm comfortably within the Local Group , our galactic neighborhood . As for multitude , the swarm sits between 30 million and nearly 500 million Solar masses — not huge , but enough to be considered a galaxy in its own rightfulness .
But what gives AC G185.0–11.5 its neat recording label of “ dark coltsfoot ” is its dark topic content . The researchers believe the cloud is keep together by a massive dark matter halo , make it an idealistic grim galax campaigner — a theoretic type of wandflower made mostly of dark matter , with niggling or no seeable stars .
This is n’t the first time scientist have suspect that some gamey - velocity clouds might actually be hidden galaxy , but most other campaigner have lacked clear rotation or have been too difficult to secernate from the Milky Way ’s halo . AC G185.0–11.5 looks like the real tidy sum — potentially the best evidence yet for a galaxy that ’s all marrow and no spud . You make out , if potatoes were stars .
If the campaigner dark galaxy is confirmed as such , it could rewrite how we recall about galaxy formation . The cloud propose a tantalizing hint about where all the “ miss ” pocket-size galaxies might be enshroud — not missing , just sit lightless in plain sight .
AstronomygalaxiesGalaxy GasRadio telescopes
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