Record signal from a distant galaxy is the farthest of its kind ever detected

(ORDO NEWS) — Hydrogen is the key building block of the cosmos. Whether stripped down to a charged nucleus or reassembled into a molecule, the nature of its presence can tell you a lot about the features of the universe on the largest scales.

For this reason, astronomers are very interested in detecting signals from this element, wherever it is.

Now, the light signature of uncharged atomic hydrogen has been measured farther from Earth than ever before, by some margin.

The Metrewave Giant Radio Telescope (GMRT) in India picked up the signal with a lookback period – the time between emission and detection of light – a whopping 8.8 billion years.

This gives us a fascinating glimpse into some of the earliest moments in the universe, which is currently estimated to be around 13.8 billion years old.

“The galaxy is emitting different kinds of radio signals,” says cosmologist Arnab Chakraborty of McGill University in Canada.

“Until now, it has only been possible to capture this particular signal from the nearest galaxy, limiting our knowledge to those galaxies closer to Earth.”

In this case, the radio signal emitted by atomic hydrogen is light. wave length 21 cm.

Long waves are not very energetic and light is not intense, making them difficult to detect at a distance; the previous record hindsight time was only 4.4 billion years.

Due to the enormous distance it traveled before it was intercepted by GMRT, the 21 cm emission line was stretched by expanding the space to 48 centimeters, i.e. a phenomenon described as the redshift of light.

The team used gravitational lensing to detect a signal from a distant star-forming galaxy called SDSSJ0826+5630.

Gravitational lensing is when light is magnified as it follows the curved space surrounding a massive object that sits between our telescopes and the primordial source, effectively acting like a huge lens.

“In this particular case, the signal is distorted due to the presence of another massive body, another galaxy, between the target and the observer,” says astrophysicist Nirupam Roy from the Indian Institute of Science.

“This actually results in a 30x magnification of the signal, allowing the telescope to pick it up.”

The results of this study will give astronomers hope that they will be able to make other similar observations in the near future: distances and lookback times that were previously out of the question are now largely within reason. If the stars align, that is.

Atomic hydrogen is formed when hot ionized gas from the vicinity of a galaxy begins to fall onto the galaxy, cooling along the way. Eventually, it turns into molecular hydrogen and then into stars.

Being able to look that far into the past could tell us more about how our own galaxy originally formed, as well as lead astronomers to a better understanding of how the universe behaved when it first began.

These latest discoveries “will open up exciting new possibilities for investigating the cosmic evolution of neutral gas with existing and future low-frequency radio telescopes in the near future,” the researchers write in the published paper.


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