Hubble Space Telescope suggest the formation of the first stars and galaxies in the early universe took place sooner than previously thought.The exploration of the very first galaxies remains a significant challenge in modern astronomy. We do not know when or how the first stars and galaxies in the universe formed. Hubble Space Telescope through deep imaging observations. Hubble Space Telescope through deep imaging observations has been trying to answer some of these astronimcal questions.
A team of European researchers, led by Rachana Bhatawdekar of ESA (the European Space Agency), set out to study the first generation of stars in the early universe. Known as Population III stars, these stars were forged from the primordial material that emerged from the big bang. Population III stars must have been made solely out of hydrogen, helium and lithium, the only elements that existed before processes in the cores of these stars could create heavier elements, such as oxygen, nitrogen, carbon and iron.
Bhatawdekar and her team mentioned “We found no evidence of these first-generation Population III stars in this cosmic time interval,” said Bhatawdekar of the new results.” . This statement was released based on the research they conducted on probed the early universe from about 500 million to 1 billion years after the big bang by studying the cluster MACS J0416 and its parallel field with the Hubble Space Telescope.The result was achieved using the Hubble Space Telescope’s Wide Field Camera 3 and Advanced Camera for Surveys, as part of the Hubble Frontier Fields program.
This program (which observed six distant galaxy clusters from 2012 to 2017) produced the deepest observations ever made of galaxy clusters and the galaxies located behind them which were magnified by the gravitational lensing effect, thereby revealing galaxies 10 to 100 times fainter than any previously observed. The masses of foreground galaxy clusters are large enough to bend and magnify the light from the more distant objects behind them. This allows Hubble to use these cosmic magnifying glasses to study objects that are beyond its nominal operational capabilities.
Bhatawdekar and her team developed a new technique that removes the light from the bright foreground galaxies that constitute these gravitational lenses. This allowed them to discover galaxies with lower masses than ever previously observed with Hubble, at a distance corresponding to when the universe was less than a billion years old. At this point in cosmic time, the lack of evidence for exotic stellar populations and the identification of many low-mass galaxies supports the suggestion that these galaxies are the most likely candidates for the reionization of the universe. This period of reionization in the early universe is when the neutral intergalactic medium was ionized by the first stars and galaxies.
“These results have profound astrophysical consequences as they show that galaxies must have formed much earlier than we thought,” said Bhatawdekar. “This also strongly supports the idea that low-mass/faint galaxies in the early universe are responsible for reionization.”
This leaves an exciting area of further research for the upcoming NASA/ESA/CSA James Webb Space Telescope — to study the universe’s earliest galaxies.
Photos Credits : Nasa Hubble telescope