Researchers detect radio signals from faraway galaxy 

Discovery, innovation and research are now on an all-time high in the field of space studies or what we popularly understand as astronomy. Recently, scientists based at McGill University in Canada and the Indian Institute of Science (IISc), Bengaluru have made a ground-breaking discovery. Wondering what it is? Well, they have detected radio signals from atomic hydrogen (primary fuel for star formation in galaxies) in a faraway galaxy, located more than 9 billion light years away from the Earth.  

So far, it is the farthest astronomical distance across which such a signal has been captured. Okay, but how was this made possible? By using a unique wavelength called “21-centimetre line” or the “hydrogen line” which is nothing but wavelength emitted by neutral hydrogen atoms. Astronomers predict that this brand-new discovery can open an array of understanding into the formation of the universe. Also, this is the first time that the hydrogen line wavelength has been used. The latest finding has been published in the journal Monthly Notices of the Royal Astronomical Society.  

Now for those unaware, this study sheds light on how a galaxy is formed. Turns out, from the atmosphere surrounding a galaxy, hot and ionised gas is formed that eventually enters the galaxy itself, cools down and finally forms atomic hydrogen. This in turn converts into molecular hydrogen, ending up in the formation of stars.  

Sources also cite that the hydrogen line wavelength directly indicates that atomic hydrogen is present in the galaxy, as it is the only one that is capable of emitting radio waves. Do you know how these radio signals can be measured? By using low-frequency radio telescopes such as the Giant Metrewave Radio Telescope or the GMRT, located in Pune.  

However, so far, such radio signals located so far away, exhibiting weak wavelengths were nearly impossible to detect. In fact, till date, the farthest galaxy located was at a distance of 4.1 billion light years away only. Okay, so what exactly did the scientists do that radio signals located 9 billion light years away were also easily detected? They divided the 9 billion into two halves: A 4.1 billion, the data of which were already present and then targeted the rest 4.9 billion this time around. As expected, detecting radio waves in such a way was a lot easier. Experts suggest that this will not only offer new insights about the formation of stars in a galaxy or the universe but also throw light on the evolution of neutral gas such as the atomic hydrogen at different cosmological space and time.  

Interestingly, a phenomenon called gravitational lensing has further made this discovery successful. As part of it, light from a source is bent, in turn magnifying the signal, such as radio waves in this case, which was magnified almost 30 times over.