[csusbpeace] Uncovering Secrets of the Early Universe: Astronomers Capture Radio Signal From Distant Galaxy
- From: "raccoon" <dmarc-noreply@xxxxxxxxxxxxx> ("bigraccoon1")
- To: "CSUSBPEACE@xxxxxxxxxxxxx" <CSUSBPEACE@xxxxxxxxxxxxx>
- Date: Thu, 19 Jan 2023 08:16:41 -0800
https://scitechdaily.com/uncovering-secrets-of-the-early-universe-astronomers-capture-radio-signal-from-distant-galaxy/
Uncovering Secrets of the Early Universe: Astronomers Capture Radio Signal
From Distant Galaxy
January 18, 2023
<https://scitechdaily.com/images/Giant-Metrewave.jpg>One of the dishes of
the Giant Metrewave Radio Telescope (GMRT) near Pune, Maharashtra, India.
Credit: National Centre for Radio Astrophysics
Probing galaxies at much greater distances from Earth may now be within reach.
How do stars form in distant galaxies? Astronomers have long been trying to
answer this question by detecting radio signals emitted by nearby galaxies.
However, these signals become weaker the further away a galaxy is from Earth,
making it difficult for current radio telescopes to pick up.
Now researchers from Montreal and India have captured a radio signal from the
most distant galaxy so far at a specific wavelength known as the 21 cm line,
allowing astronomers to peer into the secrets of the early universe. With the
help of the Giant Metrewave Radio Telescope in India, this is the first time
this type of radio signal has been detected at such a large distance.
<https://scitechdaily.com/images/Signal-Detection-From-Distant-Galaxy-scaled.jpg>Illustration
showing detection of the signal from a distant galaxy. Credit: Swadha Pardesi
“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,” says Arnab Chakraborty, a
Post-Doctoral Researcher at McGill University under the supervision of
Professor Matt Dobbs.
“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,” he adds.
A look back in time to the early universe
For the first time, the researchers were able to detect the signal from a
distant star-forming galaxy known as SDSSJ0826+5630 and measure its gas
composition. The researchers observed the atomic mass of the gas content of
this particular galaxy is almost twice the mass of the stars visible to us.
<https://scitechdaily.com/images/Radio-Signal-Distant-Galaxy.jpg>Image of
the radio signal from the galaxy. Credit: Chakraborty & Roy/NCRA-TIFR/GMRT
The signal detected by the team was emitted from this galaxy when the
universe was only 4.9 billion years old, enabling the researchers to glimpse
into the secrets of the early universe. “It’s the equivalent to a look-back
in time of 8.8 billion years,” says Chakraborty, who studies cosmology at
McGill’s Department of Physics.
Picking up the signal from a distant galaxy
“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,” says
co-author Nirupam Roy, an Associate Professor in the Department of Physics at
the Indian Institute of Science.
According to the researchers, these results demonstrate the feasibility of
observing faraway galaxies in similar situations with gravitational lensing.
It also opens exciting new opportunities for probing the cosmic evolution of
stars and galaxies with existing low-frequency radio telescopes.
Reference: “Detection of H I 21 cm emission from a strongly lensed galaxy at
z ∼ 1.3” by Arnab Chakraborty and Nirupam Roy, 23 December 2022, Monthly
Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stac3696 <https://doi.org/10.1093/mnras/stac3696>
The Giant Metrewave Radio Telescope was built and is operated by NCRA-TIFR.
The research was funded by McGill University and the Indian Institute of
Science.
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