Record-Breaking Signal from the Far Galaxy

Record-Breaking Signal from the Far Galaxy
Record-breaking Signal from the Far Galaxy - Image of the radio signature for atomic hydrogen from the galaxy. (Chakraborty & Roy/NCRA-TIFR/GMRT)

The primary building block of the universe is hydrogen. The nature of an object's existence, whether reduced to its charged nucleus or compressed into a molecule, can reveal a lot about the properties of the Universe at the largest scales.

Therefore, wherever this element can be found, astronomers are particularly interested in finding signals from it.

For the light signature of uncharged atomic hydrogen, it was measured as more distance from Earth than usual.

The 8,8 billion-year-old signal was detected by the Giant Meter Wave Radio Telescope (GMRT) in India.

This gives us a fascinating window into some of the earliest moments in the Universe, which is now thought to be around 13,8 billion years old.

Galaxies produce many types of radio radiation, according to Canadian cosmologist Arnab Chakraborty of McGill University. The signal in question has so far only been recorded from a nearby galaxy, limiting our understanding to galaxies closer to Earth.

In this example, atomic hydrogen emits a light wave with a wavelength of 21 centimeters as a radio signal. The previous record return time was just 4.4 billion years, making long waves difficult to detect from afar as they are neither extremely powerful nor light-intense.

The 21-centimeter emission line was stretched to 48 centimeters by the expansion of space due to the great distance traveled before it was captured by GMRT, a phenomenon known as redshift of light.

The signal was discovered by the team using gravitational lensing and comes from the distant star-forming galaxy SDSSJ0826+5630. Light is magnified by gravitational lensing, which occurs when a large object between our telescopes and the original source of light bends light as it travels around it.

According to astrophysicist Nirupam Roy of the Indian Institute of Science, “in this particular scenario the signal is distorted by the presence of another massive object, another galaxy, between the target and the observer.

"This effectively magnifies the signal by 30 times and makes it visible to the telescope."

The findings of this study will give astronomers hope that more similar observations will be made soon, as previously unattainable distances and backtracking time periods are now very possible. Of course, if everything falls into place.

Hot, ionized gas from around a galaxy begins to fall into the galaxy and cools along the way, forming atomic hydrogen. Eventually it turns into molecular hydrogen and stars.

Because we can go this far back in time, we can learn more about the early formation of our own galaxy, and astronomers can better understand the early behavior of the Universe.

These latest discoveries "offer fascinating new options for investigating the cosmic evolution of neutral gas with current and future low-frequency radio telescopes in the near future," according to the researchers' published study.

Source: sciencealert – academic.oup.com/mnras/article/519/3/4074/6958817

Günceleme: 21/01/2023 13:50

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