(ORDO NEWS) — A group of astronomers have developed a method that will allow them to “see” through the fog of the early universe and detect light from the first stars and galaxies.
Under the auspices of the University of Cambridge, researchers have developed a methodology that will allow them to observe and study the first stars through the clouds of hydrogen that filled the universe about 378,000 years after the Big Bang.
The Square Kilometer Array (SKA) is a next-generation telescope that should be completed by the end of the decade. It will likely be able to take images of the earliest light in the universe. For modern telescopes, the difficulty lies in detecting the cosmological signals of stars through dense hydrogen clouds.
The use of the radio telescope itself creates distortions in the received signal, which can completely hide the desired cosmological signal. In modern radio cosmology, this is an extremely difficult task. Such distortions are considered the main obstacle in this type of observation.
Now, under the auspices of Cambridge, a team of scientists has developed a methodology to see through primordial clouds and other noisy sky signals while avoiding the distortion introduced by a radio telescope.
Their methodology is part of the REACH (Radio Space Hydrogen Analysis) experiment. It will allow astronomers to observe the earliest stars through their interactions with hydrogen clouds. The process is similar to guessing the landscape from the outlines in the fog.
Their method will improve the quality and reliability of observations of this unknown and pivotal moment in the evolution of the universe. The first REACH sightings are expected later this year.
In 2018, another research group (who ran the “Global Reionization Epoch Signature Detection Experiment” or EDGES) published a result hinting at the possible detection of this earliest light, but astronomers were unable to replicate the result and everyone began to believe that the original result could be related with interference from the telescope used.
To study this period of the universe’s development, often referred to as the Cosmic Dawn, astronomers study the electromagnetic radiation signature of hydrogen in the early universe, which looks like a 21-centimeter line.
They are looking for a radio signal that will show the contrast between the radiation from the hydrogen itself and the radiation behind the hydrogen fog.
The methodology developed by Dr. Ela de Lera Acedo and colleagues at the University of Cambridge uses Bayesian statistics to detect the cosmological signal from telescope interference and general celestial noise to separate these signals.
This required the most modern techniques and technologies from different fields.
The researchers used simulations to mimic a real-world observation using multiple antennas, which would increase the reliability of the data early observations relied on a single antenna.
“Our method jointly analyzes data from multiple antennas over a wider frequency range than equivalent state-of-the-art instruments. This approach will give us the necessary information for Bayesian data analysis,” said de Lera Acedo.
“Essentially, we ditched traditional design strategies and instead focused on designing a telescope that fits our data analysis plan sort of like a reverse design. This could help us explore things like the Cosmic Dawn or the era of reionization, when the hydrogen in the universe was reionized.”
The telescope is currently being completed at the Karoo Radio Reserve in South Africa. The site was chosen because of its excellent conditions for radio observations of the sky. It is far from man-made radio frequency interference, such as TV and FM radio signals.
Professor de Villiers, co-leader of the project at Stellenbosch University in South Africa, said: “While the antenna technology of this instrument is quite simple, the harsh and remote deployment conditions, as well as the tight manufacturing tolerances, make this project challenging.”
“We’ll be happy to see how well the system performs and are fully confident that we can make this discovery possible.”
The Big Bang and the earliest periods of the universe have been well understood through studies of the cosmic microwave background (CMB) radiation.
The late and large-scale evolution of stars and other celestial objects has been studied even better. But the timing of the formation of the first light in the Cosmos is a fundamental missing piece in the puzzle of the history of the universe.
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