NASA’s Hubble discovers galaxy star birth mechanism

Washington: Astronomers have uncovered a unique process for how the universe’s largest galaxies continue to producing stars long after their peak years of star birth. NASA’s Hubble Space Telescope allowed the astronomers to see brilliant knots of hot, blue stars forming along the jets of active black holes found in the centres of giant elliptical galaxies.

Combining Hubble data with observations from a suite of ground-based and space telescopes, two independent teams found that that the black hole, jets, and newborn stars are all parts of a self-regulating cycle. High-energy jets shooting from the black hole heat a halo of surrounding gas, controlling the rate at which the gas cools and falls into the galaxy.

The “raindrops” eventually cool enough to become star-forming clouds of cold molecular gas.This discovery explains the mystery of why many elliptical galaxies in the present-day universe are not ablaze with a higher rate of star birth. An earlier independent study, led by Rupal Mittal of the Rochester Institute of Technology and the Max Planck Institute for Gravitational Physics, also analysed the star-birth rates in the same galaxies as Tremblay’s sample.