What is a dwarf galaxy? What did Indian astrophysicists find out about its origins?
Several long-standing mysteries about the universe are being solved as science advances. One such recent puzzle, why dwarf galaxies have active star formations, has been solved by a team led by Indian astrophysicists. Let’s find out what that discovery is!
What is a dwarf galaxy?
A dwarf galaxy is a small galaxy that is much smaller than our Milky Way galaxy. They are usually distinguished by concentrated star formation in the centre. They contain between 1000 and tens of billions of stars, as opposed to the Milky Way’s 200-400 billion stars. The Large Magellanic Cloud, which contains over 30 billion stars, is one such example that is sometimes classified as a dwarf galaxy.
What did the research find out?
The researchers observed signals from the outskirts of a galaxy that was no more than 150 million years old, indicating the formation of stars beyond visible boundaries. The discovery was made onboard AstroSat by India’s first dedicated multi-wavelength space observatory, the UltraViolet Imaging Telescope (UVIT).
Researchers discovered faint emissions of Far UltraViolet (FUV) light on the outskirts of distant Blue Compact Dwarf (BCD) galaxies 1.5 – 3.9 billion light-years away. The discovery is a significant step toward unravelling the mysteries of galaxy formation.
Prof. Kanak Saha of the Inter-University Center for Astronomy and Astrophysics (IUCAA), Pune, conceived the study, and Anshuman Borgohain, a recipient of the INSPIRE Fellowship from the Department of Science and Technology (DST) and researcher at Tezpur University, is the lead author of the article published in the journal Nature.
“The resolving power of UVIT and UV deep field imaging techniques has been the key to spotting these very young, large star-forming clumps. Due to their large distances from us, it was a challenging task to establish the detection of these faint, extremely blue star-forming clumps with million solar masses,” said Prof. Kanak Saha, highlighting that it helped to witness the ‘live’ formation of these far-way dwarf galaxies.
Principal research staff in the IBM Research Division, USA, Dr Bruce Elmegreen, who contributed to the study, said, “It has been a mystery how some small galaxies like these can have such active star formation. These observations suggest that accreting gas in the far outer parts can be forced to move inward through torques exerted by giant gas and stellar complexes. This migration builds up the central density over the galaxy’s lifetime.”
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