The Milky Way is not alone in our corner of the Universe . It is surrounded by dozens of little fellow traveler galaxies , some orbiting very close and some further out . Researchers have now announced the find of a new dwarf galaxy and it does n’t depend quite how we would expect .
The object is call Antlia 2 , or Ant 2 , and it does n’t seem to be quite there . Let us excuse : It is massive , as with child as one - third of the Milky Way , but exceedingly faint . It is like in size to the prominent Magellanic Cloud ( LMC ) , one of our two astronomical comrade seeable to the naked eye , but it ’s 10,000 times fainter . Basically , it is either far too great for its luminance or far too dimmed for its size . A newspaper report the find is available onArXiv .
“ This is a ghost of a galaxy , ” Gabriel Torrealba , the report ’s booster cable writer from the University of Cambridge , say in astatement . “ Objects as diffuse as Ant 2 have simply not been visit before . Our discovery was only possible thanks to the quality of the Gaia data . ”
Gaia is the flagship European mission that is mapping the situation ofbillions of starsfrom the Milky Way and beyond . Its high precision measurements have allow researchers to cut through the motion of millions of stars , which is how they discovered a radical of distant stars run together . After this first analysis , the researchers used the Anglo - Australian Telescope to study 100 more stars , which allowed them to approximate the distance and the great unwashed of Ant 2 .
It is place 130,000 faint - days from the Milky Way and is over 13 million times profound than the Sun . For a extragalactic nebula , though , that is definitely on the calorie-free side . The LMC , for model , is almost 1,000 times heavy .
“ The simplest explanation of why Ant 2 appears to have so trivial mass today is that it is being take apart by the Galactic tides of the Milky Way , ” said co - source Sergey Koposov from Carnegie Mellon University . “ What remains unexplained , however , is the object ’s giant size of it . Normally , as galaxies lose mass to the Milky Way ’s tides , they reduce , not grow . ”
One possible explanation is that Ant 2 form in a region of space where dark matter was not very impenetrable and due to inner processes like supernova explosion and starring winds , gas spreads out . Over clip star forge at these edges , and the little galaxy stupefy its current sizing . But this explanation necessitate either very efficient explosion or dour matter behaving otherwise to how we gestate . It is unclear at the bit what the dominant factor is .
“ Compared to the rest of the 60 or so Milky Way orbiter , Ant 2 is an geek , ” said co - generator Matthew Walker . “ We are wonder whether this Galax urceolata is just the tip of an iceberg , and the Milky Way is surrounded by a magnanimous population of nearly invisible dwarfs similar to this one . ”
