N. Fisher, h. Pfeiffer, a. Bunanno, SXS Collaboration
Physicists prey on merging black holes and other similar cosmic phenomena by identifying gravitational waves, from which they can collect valuable information, such as a set of both the anterior black hole and the final, large black hole. According to a new paper published in the journal Nature Communications Physics, a team of scientists has now found evidence of supercomputer-computer simulations that can encode the shape of waves merging black holes even as they settle into their final form.
General relativity predicts that two merged black holes will give powerful gravitational waves – ripples in the space-time fabric so obscured that they are very difficult to detect. The waveform of those signals serves as the audio dio fingerprint of two black holes that propagate inward towards each other and merge in the event of a massive collision, sending powerful shock waves during space time. Physicists find a so-called “chip” pattern in the data with two black holes colliding. The new residual black hole vibrates under the influence of that influence, and those vibrations – called “ringdowns” because they sound like bells – also produce gravitational waves. Moreover, gravitational-wave signals have several frequencies, called “overtones”, each tone corresponding to the vibrational frequency of a new black hole.
LIGO detects these gravitational waves through laser interferometry, in which small changes in distance between objects other than two kilometers can be measured using high-powered lasers. (LIGO has detectors in Hanford, W., Washington, and Louisiana, while Italy’s third detector, Advanced VIRGO, arrived online in 2016.) On September 14, 2015, at 5:51 a.m. EDT, both detectors gave signals in milliseconds. Each other for the very first time.
Since then, LIGO has been upgraded and has scored two more runs, starting the third run on April 1, 2019. Within a month, the collaboration found more than five gravitational wave events: three from a black hole merging, one from a neutron star merger. , And another that may be the first example of a neutron star / black hole merger.
Most recently, in June 2020, the partner announced an investigation into the binary black hole merger on May 21, 2019 (designated S190521g). And just last month, LIGO / Virgo collaborated to announce that it had received a gravitational wave signal from another black hole merger. This was the most comprehensive and far-reaching merger discovered by collaboration and has created the most energetic signal detected so far. It is shown in the data as more of a “bang” than a normal “churp”. The investigation also marked the first direct observation of an intermediate mass black hole.
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Artist’s depiction of part of a black hole.
C. Evans; Jesse Bustillo.
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Stages of Black Hole Merger. The first signal shows a typical “churching” signal. The other three show that, after a collision, the frequency decreases and increases again, which produces a second excitement.
C. Evans, j. Calderon Bustillo
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Details of the shape of the black hole remaining after the collision of the black hole, “Chestnut shape.” Gravity-wave emission (in yellow) regions of the cluster near its group.
C. Evans, j. Calderon Bustillo
According to Christopher Evans, a graduate student at Georgia Tech and co-author of this latest paper, he and his colleagues performed a supercomputer simulation of a black hole collision and then compared the gravitational waves emitted by a residual black hole to its rapidly changing shape. It turns out that standard gravity-wave observations typically study mergers from the top of a residual black hole. While the team looked at the phenomenon from the perspective of the fossil equator, the simulations showed that gravitational wave signals are “much richer and more complex than we normally would consider,” Evans said.
“When we looked at the black holes from their equator, we discovered that the final black hole emits a more complex signal, which goes up and down a few times before it dies,” said Juan Calderon Bustillo, co-author of the Galician Institute. Said. Santiago de Compostela, Spain for higher energy physics. “In other words, black holes actually chip in many times.”
And that more complex signal seems to encode information about what the final relic black hole will shape. “While the two original,‘ parent ’black holes are of different sizes, the final black hole initially looks like a chest, one part on one side and wide, smooth on the other,” Bustillo said. “It turns out that the black hole emits more intense gravitational waves through its most curved fields, which surround its corps. This is because the residual black hole also spins and its part and back repeatedly point to all observers. , Produces multiple chips. “
The authors conclude that the existing sensitivity of LIGO / VIRGO detectors should be sufficient to observe the chip signature in their data after this merger.
DOI: Communications Physics, 2020. 10.1038 / s42005-020-00446-7 (About DOI).
