ORLANDO, January 11, 2021 – Data from the Arecibo Observatory in Puerto Rico was used to help detect the first possible signals of low-frequency disturbances in space-time curvature.
The results were presented today at the 237th meeting of the Astronomical Society of America, held almost, and published in The Astrophysical Journal Letters. The Arecibo Observatory is managed by the University of Central Florida for the National Science Foundation under a collaboration agreement.
The collisions, which pass through space as a result of the movement of very large objects, such as black holes orbiting each other or hitting neutron stars, are called gravitational waves.
Understanding these waves is important because they give us an insight into the history of the cosmos and extend researchers ’knowledge of gravity beyond the boundaries of conventional understanding.
Although the waves of gravity stretch and press on space-time clothing, they do not affect humans and any changes in the relative distances between objects would change a person’s height by less than one. percent of human hair width. , says Joseph Simon, a graduate fellow at the Center for Astrophysics and Space Astronomy at the University of Colorado Boulder.
Simon presented the association’s findings today, is a lead researcher on the paper, and is a member of the North American Nanohertz Observatory for Gravitational Waves, or NANOGrav, the team that produced the research.
NANOGrav is a group of more than 100 astronauts from across the U.S. and Canada that aims to study the universe using low-frequency gravitational waves.
In 2015, the NSF Gravitational-Wave Interferometer (LIGO) Laser Observatory performed the first direct observation of high-frequency gravitational waves using interferometry, a measurement method that uses electromagnetic wave interpolation.
The new findings made by NANOGrav researchers are unique in that the astronauts were detecting potential signals of low frequency gravitational waves using radio telescopes, since LIGO cannot detect them. Both frequencies are important for understanding the universe.
At the heart of the research were two NSF-funded instruments – the Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.
The Arecibo Observatory, with its 1,000-foot diameter dish, provided very detailed data, while the Green Bank Telescope, which has a much larger sky cover, sampled a wider range of information. ‘needed to distinguish gravitational waves from other influences,’ says Simon.
“We spend about half the pulsars with each telescope,” he says. “Each telescope takes about half of our total sensitivity in a complementary way.”
Although the researchers used Arecibo data for the study, they can no longer observe it since the observatory collapsed in December after broken cables in August and November.
“It was a terrible day when the telescope crashed,” says Simon. “It feels like the loss of a good friend, and we are so sorry for our friends and colleagues in Puerto Rico. Going forward, we hope the time we spend on Telescope Increase the Green Bank to compensate at least to some extent for Arecibo ‘s loss. Another large collection area radio telescope will soon need to be built in the US if we are to grow this area of research. “
The researchers were able to detect potential signals of low-frequency gravitational waves by using the telescope to study signals from pulsars, which are small, dense, rotating stars that which emits the pulses of radio waves at precise moments towards the Earth.
These regularities make them useful in astronomical study, and are often referred to as the keepers of the earth’s time.
Gravity waves can disrupt the regularity, causing movements in pulsar signals reaching the Earth, thus indicating that the Earth’s position has shifted slightly.
By studying the time of the constant signals from multiple pulsars scattered across the sky at the same time, known as the “pulsar timing sequence,” NANOGrav was able to detect minute changes in Earth’s position possibly due to gravitational waves. stretching and shrinking space-time.
NANOGrav was able to control some effects in addition to gravitational waves, such as obstruction from the case in the solar system or specific errors in the data collection.
To confirm the direct detection of a signature from low-frequency gravitational pulses, NANOGrav researchers need to detect a specific pattern in the signals between individual pulsars. At this point, the signal is too weak for such a pattern to be different, according to the researchers.
Promoting the signal NANOGrav needs to expand their database to include more pulsars that have been monitored for even longer periods, which increases the sensitivity of the field. In addition, NANOGrav data combined with data from other pulsar time array experiments, a joint effort with the International Pulsar Timing Array, may reveal such a pattern. The International Pulsar Timing Array is a collaboration of researchers using the world’s largest radio telescopes.
At the same time, NANOGrav is developing ways to ensure that the detected signal could not be from another source. They make computer simulations that help test whether the detected sound could be caused by effects in addition to gravity waves, to avoid false detection.
“It’s very interesting to see such a strong signal emerge from the data,” says Simon. “However, because the gravitational wave signal we are looking for spans the length of our look, we have to understand our sound carefully. This leaves us in a very interesting place, where we can rule out some known sound sources, but we still cannot say whether the signal is in fact from gravitational waves. For that, we will need more data. ”
Benetge Perera, a scientist at the Arecibo Observatory who is an expert in using pulsars observation to detect gravitational waves, says the research aims to open a new window in the frequency spectrum of gravitational waves.
“The detection of low-frequency gravitational waves would improve our understanding of supermassive black hole binaries, galaxy evolution, and the universe,” says Perera, who is also a member of NANOGrav.
He says that despite the collapse of the Arecibo Observatory, much archival data remains to be discovered to continue learning about the waves of gravity.
“Arecibo was very important because its temporal data provided about 50 percent of NANOGrav’s sensitivity to gravitational waves,” he says. “I want to make sure that the sensory data we collected before the fall of Arecibo gets the highest scientific impact.”
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INFORMATION: Robert H. Wells, Audit Office, [email protected]