The new gravitational shadow detected by the NASAOGrav observatory comes from a supermassive black hole billions of times more massive than the Sun, which could reveal the nature of the universe.
Astronomers first discovered giant ripples in the spacetime domain. Gravitational balls of this size are thought to originate from the merger of supermassive black holes, each billions of times more massive than the Sun, National geographic On June 28, it was reported.
Simulation of two supermassive black holes circling each other.
Simulation of two supermassive black holes rotating around each other. (Photo: National Geographic).
Ƭby studying the temporal fluctuations of the radio bursts of a rotating stellar carcass called pulsara group of scientists from North American Nanohertz Gravitational Wave Observatory (NANOGrav) can receive the aforementioned gravitational waves. Their future study could reveal clues to the first moments after the Big Bang, helping uncover mysteries like the nature of dark matter, which makes up five-sixths of the matter in the universe.
When an object with mass accelerates, it creates distortions called gravitational waves that travel at the speed of light, stretching and compressing the space-time field along the way. Gravitational waves were predicted by Albert Einstein in 1916. Scientists discovered the first evidence of gravitational waves with the Laser Interferometer Gravitational Wave Observatory (LIGO) in 2015.
Since light has many kinds of wavelengths and frequencies, from short-wavelength high-frequency gamma rays to long-wavelength low-frequency radio waves, so do gravitational waves. . LIGO detects high frequency gravitational waves with a wavelength of approximately 2,896 km/h. Now the NANOGrav team has found low-frequency gravitational waves with wavelengths so long that light takes years or decades to travel between its two peaks. They detailed their findings in five studies published in Astrophysical Journal Letters.
To identify these giant ripples, scientists need a collection of sensors larger than Earth. For the past 15 years, NANOGrav has been analyzing dead stars in the Milky Way to create a galaxy-sized gravitational wave detector. They focused on millisecond quasars, which are born when the massive star dies in a supernova explosion, leaving behind a rapidly spinning body. The extremely dense stellar remnant emits a double radio beam from the magnetic pole, flashing like a beacon. Each time the light beam sweeps across the Earth, the radio telescope detects a pulse. Hundreds of radio pulses appear every second with extreme precision.
The team tracked 68 pulsars a few thousand light-years from Earth. Gravitational waves cause the space-time field to stretch, which changes the time interval between radio pulses, causing some pulses to slow down while others speed up in discrete and predictable ways. . This oscillation is also seen in pulsar pairs in a pattern that depends on the distance between the two stars in the system, suggesting that gravitational waves affect both.
Pulsating stars produce very weak radio sources, so to conduct this study, scientists spend thousands of hours per year observing with the world’s largest radio telescopes, including the Frecibo Observatory in Puerto Rico, the Observatory of Green Bank in West Virginia and the Verу Large Array. in New Mexico. As a result, they were able to detect when the radio pulse appeared to within a microsecond.
Most likely, the source of the newly discovered radio waves is a pair of supermassive black holes between 100 million and 10 billion times larger than the Sun. In contrast, the gravitational waves detected by LIGO came from the collision between two smaller black holes or neutron stars with masses of only a few tens of suns. Astronomers believe that supermassive black holes are found at the center of the largest galaxies in the universe. When the two galaxies merge, the black hole at the center moves into the new galactic nucleus, forming a binary system that generates gravitational waves as the two supermassive black holes slowly spin around each other.
As ANOGrav collects more data over time, the team hopes the instrument is sensitive enough to identify gravitational waves from a particular black hole binary system. This will allow them to combine detection with other observatories to analyze the target, using both light and gravity.
Article source: VnExpress
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The new gravitational waves detected by the NANOGrav observatory come from a supermassive black hole, which is billions of times more massive than the Sun. This has…
