About 400 million years ago, the universe was very dark until the first star producing galaxies started to make ultraviolet light, which ultimately lighted up the cosmos.
Recently, NASA-funded research team with grant number 12886 at the Johns Hopkins University discovered a compact galaxy named as J0921+4509. The researchers believed that it possesses similar characteristics needed to lighten up the early universe. It is actually emitting photons with an energy that ionize hydrogen atoms. This galaxy also enables over 20% of its ultraviolet radiation to leak through the dust clouds causing it to emit strong levels of ultraviolet light and providing hints to astronomers on how the earliest galaxies of the universe may have likely behaved.
J0921+4509 is located 2.9 million years away from the Milky Way galaxy. It generates stars in a compact region similar to the rate of budding galaxies of earliest times. Moreover, the galaxy whips around 50 stars having the same mass as the sun every year that is 33 times more than the number of stars that the Milky Way produces for the same period.
Brian Siana, an astronomer from the University of California, Riverside stated that, “That’s quite high. This is roughly the fraction that we think all galaxies in the early universe had to have in order to ionize the hydrogen in the intergalactic medium.”
Thousands of years after the Big Bang, the cosmic scattered protons and electrons started to cool and developed the first atom of hydrogen. The fact ultimately resulted in the creation of hydrogen walls along with the clouds of cosmic dust, which has the ability to absorb ultraviolet radiation. This averted light from fleeing and blotched the dark ages of the universe.
With the passage of time, these radiations become too strong that it re-ionized the hydrogen. It actually happens when the photons gather enough energy in order to break up the electrons from the hydrogen atoms, which resulted in lighting up the previously dark universe. The astronomers think that, the radiation that broke electrons come from stellar births, but they are not sure about that.
Sanchayeeta Borthakur, an astronomer from the Johns Hopkins University stated that, “The galaxies contains star forming regions that are wrapped with cold gases so the radiation won’t come out. If we want to know that how the radiation gets out of the galaxy, we need to learn the mechanisms that ionized the universe.” He further stated that, it seems that the newly discovered galaxy might provide some hints concerning how the early universe lighted up.
Moreover, the researchers have been in a long quest of finding a ‘holey’ galaxy to examine how star-produced radiation plays a role in ionization process. For this purpose, the researchers placed the particular galaxy with the help of radiation leak measurement method and Cosmic Origin Spectrograph aboard the Hubble Space Telescope. As per the statement of researcher’s team “a combination of unusually strong winds, intense radiation and a massive, highly star-forming galaxy” for the validity of the indicator.
Borthakur stated that, “The confirmation of the indicator is key and now people can use this indicator to study distant galaxies at longer wavelengths.”
The study is published in the journal ‘Science’.
