Astronomers have discovered the birth of a new galaxy in the Leo constellation-a cosmic phenomenon that is unfolding at the tip of the longest tidal tail ever recorded. The young ultra-diffuse galaxy, still in its early stages, is forming at the end of the tidal tail of galaxy NGC 3785, approximately 435 million light-years from Earth. This finding gives insight into how galaxies are formed, influenced by the gravitational forces of surrounding celestial bodies.
It has involved contributions from researchers of a team put together from the Indian Institute of Astrophysics in Bengaluru, National Centre for Radio Astrophysics in Pune, Pondicherry University, and the SKA Observatory in the UK. As claimed by the Department of Science and Technology, “The discovery centres around galaxy NGC 3785, which harbours a behemoth tidal tail-a long streaming sequence of stars and gas-over 1.27 million light years in the great unknown expanse.”
The tidal tail was formed as a result of gravitational interactions between NGC 3785 and its adjacent galaxy. This resulted in the forces stretching the stars and gas into a long stream until it eventually built into the new galaxy. The paper’s first author, Chandan Watts, said, “The first is a merger, where two galaxies collide and merge, and the second is a flyby, where galaxies pass close to one another, causing matter to be pulled away from one galaxy.” In the case of NGC 3785, this is a type of flyby.
Ultra-diffuse galaxies, such as the one found in this study, are very faint, and hence they are hard to be detected like our Milky Way galaxy. According to co-author Omkar Bait, who had first noticed the long tidal tail a few years ago when he was at NCRA, “We have chosen to look at this amazing galaxy and its huge tidal tail in great detail, and continue to study its evolution for further insight.”.
