Massive ‘ghost’ galaxy Ant 2 with few stars hiding close to Milky Way

Scientists have spotted a massive ghost galaxy near the Milky Way. The galaxy, named Antlia 2 or Ant 2, existed unnoticed until now owing to its extremely faint and low density. Its location -  behind the Milky Way’s bright central disc - also gave it a perfect hiding place, say scientists.

Researchers from Imperial College London in the UK chanced upon Antlia 2 while trawling through data from the European Space Agency’s Gaia satellite.

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“This is a ghost of a galaxy. Objects as diffuse as Ant 2 have simply not been seen before. Our discovery was only possible thanks to the quality of the Gaia data,” said Gabriel Torrealba from the Institute of Astronomy and Astrophysics at Academia Sinica in Taiwan.

Know all about Antlia 2 or Ant 2 | Here’s what the scientists say

• Antlia 2 is a massive galaxy but has very few stars, challenging conventional theories of galaxy formation.
• Ant 2 is known as a dwarf galaxy. But compared to the other known dwarf galaxies orbiting the Milky Way, Ant 2 is immense.
• The galaxy is as big as the Large Magellanic Cloud (LMC), a bright satellite galaxy that is a third the size of the Milky Way itself,
• Ant 2 is also unusual because of how little light it gives out.

Compared to the LMC, Ant 2 is 10,000 times fainter, meaning that it has about one 10,000^th the number of stars.

Previous research has suggested that some dwarfs could be inflated by vigorous star formation, causing the galaxy to ‘puff up’, but the new research shows that this process would have to be remarkably efficient to explain Ant 2.

(With PTI inputs)