Hydrogen is the basic building block of the cosmos. Whether stripped down to its charged core or piled into a molecule, the nature of its existence can tell you a lot about the properties of the Universe on the largest scales.
This is why astronomers are very interested in detecting signals from this element wherever it is found.
Now uncharged, the light signature of atomic hydrogen has been measured slightly further from Earth than ever before. The Giant Meterwave Radio Telescope (GMRT) in India received a signal. review time – the time between the emission of light and its detection – a colossal period of 8.8 billion years.
This gives us an exciting look at some of the earliest moments in the Universe, which is now estimated to be 13.8 billion years old.
“A galaxy emits different types of radio signals,” says cosmologist Arnab Chakrabortyfrom McGill University in Canada. “Until now, it was only possible to capture this particular signal from a nearby galaxy, and we’ve limited our knowledge to galaxies closer to Earth.”
In this case, the radio signal emitted by atomic hydrogen is a 21-centimeter-long light wave. Long waves are not very energetic and light is not intense, making them difficult to detect from a distance; the previous record review time only 4.4 billion years.
Because of the vast distance it traveled before being caught by GMRT, the 21-centimeter emission line was stretched by expanding space to 48 centimeters; redshift your light.
The team used gravitational lensing to detect the signal from a distant star-forming galaxy named SDSSJ0826+5630. Gravitational lensing is where light is magnified and effectively acts as a giant lens, following the curved field surrounding a massive object sitting between our telescopes and the original source.
“In this particular case, the signal is bent by the presence of another large object, another galaxy, between the target and the observer.” says astrophysicist Nirupam RoyFrom the Indian Institute of Science.
“This effectively results in a 30x magnification of the signal and allows 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 reexamination times that were previously out of bounds now make sense. If the stars align, that is.
Atomic hydrogen is formed when hot, ionized gas from a galaxy’s surroundings begins to fall onto the galaxy and cools along the way. It eventually turns into molecular hydrogen and then into stars.
Being able to look back so far in time can teach us more about how our own galaxy originally formed, as well as lead astronomers to better understand how the Universe behaved when it was just beginning.
The researchers write that these latest findings will “open up exciting new possibilities for investigating the cosmic evolution of neutral gas with current and upcoming low-frequency radio telescopes in the near future.” published article.
The research was published in the journal Monthly Notices of the Royal Astronomical Society.
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