Radio signal from a distant galaxy traced by McGill University! Here’s how gravitational lensing helped Indian and Montreal researchers!
Humans have landed on the moon and many other planets of the solar system, almost making the impossible turn possible. While mankind is proud of its achievements in the space world, some mysteries of the universe still linger, enhancing mankind's thirst for these answers. Rightly so, we humans are not yet satisfied with what we know, and we pledge to continue to be on this quest of peeping into the unknown world.
Among all these mysteries of the universe, one such question that bothers many great thinkers and astronomers is the formation of stars.
Radio signals from nearby galaxies have been used to some extent to answer this question. However, getting these signals from further away galaxies becomes next-to-impossible, as radio signals become weaker in the case of faraway galaxies.
Here comes the big news!
Researchers from India and Montreal had shaken hands to capture a radio signal from a galaxy. What is special about this galaxy is that it is the most distant galaxy so far. It is at a wavelength of 21 cm line. This huge discovery has led astronomers to step into some of the most hard-to-crack mysteries of the world.
What’s so special about the tracing of the radio signal from a distant galaxy by McGill University Astronomers?
Image Source: Deccan Herald
- A radio signal at a 21 cm line from the farthest galaxy is captured.
- It is the very first time that such a type of radio signal coming out of atomic hydrogen has been captured at an extremely large distance.
- The Giant Metrewave Radio Telescope in Pune, India was made to use.
- The tracing has paved the way for studies on the composition of faraway galaxies.
- The tracing has been possible due to a natural phenomenon known as gravitational lensing.
- The farthest galaxy picked up through the 21-cm emission till now was at redshift z=0.376.
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For the very first time, the researchers have been successful in detecting the radio signal from a faraway star-forming galaxy and recording the galaxy’s gas composition. The galaxy is called SDSSJ0826+5630.
Researchers from India and Montreal have observed that this galaxy’s atomic mass of the gas content is approximately twice the mass of the stars that are visible to us.
When the universe was only around 4.9 billion years old, the signal by this galaxy was emitted. This, thus, has made it possible for researchers to peep into the secrets of the early universe.
Arnab Chakraborty, a cosmology Post-Doctoral Researcher at McGill puts it correctly by saying, “It’s the equivalent to a look-back in time of 8.8 billion years.”
So what is Gravitational lensing, after all?
Image Source: ThoughtCo
As stated above, gravitational lensing is a naturally occurring phenomenon. It takes place in a case when a large amount of matter, such as a cluster of galaxies, forms a gravitational field that distorts and magnifies light coming from distant galaxies behind it, however, in the same line of sight. The gravitational lensing effect feels similar to peeping through a huge magnifying glass.
Nirupama Roy, an Associate Professor at the Department of Physics at the Indian Institute of Science, says, “Gravitational lensing magnifies the signal coming from a distant object to help us peer into the early universe. In this specific case, the signal is bent by the presence of another massive body, another galaxy, between the target and the observer. This effectively results in the magnification of the signal by a factor of 30, allowing the telescope to pick it up.”
What do the researchers have to say about this radio signal detection?
Researchers are excited about the opportunities this radio signal tracing has opened up. A Post-Doctoral Researcher at McGill University, Canada, Arnab Chakraborty says, “A galaxy emits different kinds of radio signals. Until now, it’s only been possible to capture this particular signal from a galaxy nearby, limiting our knowledge to those galaxies closer to Earth.”
“But thanks to the help of a naturally occurring phenomenon called gravitational lensing, we can capture a faint signal from a record-breaking distance. This will help us understand the composition of galaxies at much greater distances from Earth,” the researcher added.
The IISc stated that the astronomical distance over which the radio signal has been detected is “the largest so far by a large margin”.
Here’s what McGill University tweeted!
🔭 Researchers from #Montreal and India have captured a radio signal from the most distant galaxy so far, allowing #astronomers to peer into the secrets of the early universe. @NCRA_Outreach @iiscbangalore @Physics_at_IISc @ArnabCh88024907 @RAS_Journals https://t.co/8qKP3OBz3C
— McGill University (@mcgillu) January 16, 2023
Here’s what the Physics department of IISc expressed on Twitter:
Excited to share this report of the highest redshift detection of atomic hydrogen 21cm emission, using the Giant Metrewave Radio Telescope, from a distant galaxy; the signal originated when the universe was only 4.9 billion years old (= "look back time" of 8.8 billion years). 1/4 pic.twitter.com/taDy6VOhRX
— Physics, IISc (@Physics_at_IISc) January 16, 2023
The Takeaway
As per the researchers, the results prove two possible events. One is that it is feasible to observe distant galaxies in the same way, thanks to gravitational lensing. And two, that the result makes way for many new exciting opportunities for peering into the cosmic evolution of galaxies and stars, even with the present-day low-frequency radio telescopes. The community of astronomers is glad about this outstanding achievement!
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