Aryabhatta Institute discovers dwarf galaxies' star formation in breakthrough research

A large number of galaxies in the universe are 100 times less massive than the Milky Way galaxy, and form stars at a much slower rate than the massive ones, scientists at Aryabhatta Research Institute of Observational Sciences (ARIES) discovered. According to the press release by the Ministry of Science and Technology, Government of India, the Indian scientists found that the dwarf galaxies formed new stars at a mass-normalized rate, which is nearly 10-100 times more than that of the Milky Way galaxy. The activity lasts for tens of million-years, lesser than other gigantic galaxies that take a few billion years. 

Dr. Amitesh Omar and his former student Dr. Sumit Jaiswal from Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute of Department of Science & Technology (DST), Govt. of India, observed many such galaxies using the 1.3-meter Devasthal Fast Optical Telescope (DFOT) near Nainital and the Giant Meter wave Radio Telescope (GMRT) to study these dwarf galaxies, GOI wrote in the release. “While the former operated at optical wavelengths sensitive to detect optical line radiation emanating from the ionized Hydrogen, in the latter 30 dishes of 45-meter diameter, each worked in tandem and produced sharp interferometric images via spectral line radiation at 1420.40 MHz coming from the neutral Hydrogen in galaxies,” it added. 

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Hydrogen in dwarf galaxies irregular

According to the study conducted by the ARIES team, 1420.40 MHz images of several intense star-forming dwarf galaxies indicated the low level of hydrogen. Whereas, the scientists had expected symmetric distribution of hydrogen in the orbits. Hence scientists concluded that “hydrogen in these dwarf galaxies is found to be irregular and sometimes not moving in well-defined orbits.” Team also discovered isolated clouds, plumes, and tails, and remnants indicating the collision of the galaxies.

“The optical morphologies sometimes revealed multiple nuclei and high concentration of ionized hydrogen in the central region,” researchers wrote in the release.   “Although galaxy-galaxy collision was not directly detected, various signatures of it were revealed through radio, and optical imaging and these are helping to build up a story,” it added. “The research, therefore, suggests that recent collisions between two galaxies trigger intense star formation in these galaxies.” As per the release, the findings will be published in Monthly Notices of Royal Astronomical Society (MNRAS) Journal published by the Royal Astronomical Society, the UK. 

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