We hear more and more of the Atacama Large Millimeter/Submillimeter Array located in the Atacama desert of Chile and acting as the large eye that peruses the deep space for galaxies far away.
This time, ALMA noticed how cold molecular gas was creeping towards a galaxy’s center, a process that signals star formation when the universe was still young, at only a few hundred million years. Thus, the saga of a young galaxy begins.
According to researchers working at ALMA, this finding is bound to shed light on the formation of galaxies.
“The models predicted just what we saw, which is something really exciting. That means we are going in the right direction on understanding how galaxies formed.” ,
stated the team leader Roberto Maiolino of the University of Cambridge, UK.
The stars and galaxies that astronomers typically analyze are thought to be largely different from what a young galaxy with its stars would be. Observing young galaxies as the one just discovered is a rare opportunity, so ALMA researchers are quite excited.
Most of the stars observed nowadays have more than the left-over components of the big bang, helium and hydrogen. Heavier elements are not present in the young stars and galaxies of the early universe.
This renders the stars rich in hydrogen which would lead to their accelerated growth and early explosion as supernovae. The intense radiation stemming from young stars would heat the gas in the galaxy, so new stars would be unable to create. The supernovae explosions would then blast interstellar gas out of the young galaxy.
Yet, if this is the case, how could a young galaxy survive and grow if cool gas was being devoured by the hydrogen rich stars? With the new discovery provided by ALMA, a possible answer was found.
According to the researchers, ALMA detected cool gas clouds flowing towards the center of the early universe galaxy. This was titled BDF3299 and was calculated to be only 800 million years old, following the big bang.
The reports indicate that aside ionized carbon which is a marker for cool gas that stems newborn stars, ALMA detected carbon at the center of BDF3299 and carbon gas floating at one side. The latter was not associated to any stars around, so it would act as the reserve of cold gas that could continuously fuel the formation of new stars. Either orbiting the young galaxy or near to be drawn into its center, the carbon gas cloud was the sources of newborn stars.
“Accretion of cool molecular gas is thought to be a key mechanism in galaxy evolution. This is the first time it has been seen at work in such a primordial system,”
stated one of the researchers.
With the 66 dishes working together as one giant instrument for analyzing deep space, ALMA is at the center of this discovery. The accretion process in such a young galaxy has been analyzed for the first time. Over the weeks to come, researchers hope that they will be able to release high resolution photos of the gas cloud sustaining the evolution of the galaxy.
The research was published in the Monthly Notices of the Royal Astronomical Society.
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