IUCAA study reveals cannibalisation of dwarf galaxies by Malin 1

A recent study by a team of scientists from the Pune-based Inter-University Centre for Astronomy and Astrophysics (IUCAA) has revealed that Malin 1, the largest known low-surface-brightness galaxy, is quietly cannibalising smaller dwarf galaxies, shedding new light on its hidden growth and evolution.

Malin 1 has long puzzled astronomers since its discovery, according to a press statement issued on Friday.

Its central region, roughly the size of the Milky Way’s stellar disk, resembles a lenticular galaxy, while its extremely faint spiral arms extend out to nearly 3,00,000 light-years. Despite appearing isolated and undisturbed, the galaxy has continued to transform internally, with no clear signs of interaction—until now.

Using observations from the Ultraviolet Imaging Telescope (UVIT) onboard AstroSat, the research team identified several young star-forming clumps in Malin 1’s central region.

One particularly prominent clump, known as C1, stood out due to its brightness and mass. This was unexpected, as the central region otherwise appears quenched, with little ongoing star formation.