Astroboffins hear the first smashup of big black hole swallows smaller neighbor, as grav waves open up the sky
(2020/04/21)
- Reference: 1587508459
- News link: https://www.theregister.co.uk/2020/04/21/binary_black_hole/
- Source link:
Gravitational waves from a pair of black holes with different masses - the heftier one being 30 solar masses and its lighter companion being just eight - have been observed for the first time.
Researchers working at the LIGO and Virgo, gravitational wave observatories in the US and Italy, confirmed their results this week, which is kind of unusual. Both detectors have become so sensitive that they sniffed a new candidate merger event about once every week between April 2019 to March 2020.
The confirmation of most gravitational wave measurements has become so common that they no longer make headlines. But the latest result - codenamed GW190412 - is particularly special, according to a team at the German Max Planck Institute for Gravitational Physics.
“For the very first time we have ‘heard’ in GW190412 the unmistakable gravitational-wave hum of a higher harmonic, similar to overtones of musical instruments,” [1]said Frank Ohme, leader of the Independent Max Planck Research Group “Binary Merger Observations and Numerical Relativity” at AEI.
“In systems with unequal masses like GW190412 – our first observation of this type – these overtones in the gravitational-wave signal are much louder than in our usual observations. This is why we couldn’t hear them before, but in GW190412, we finally can.”
The signals were emitted when the binary black hole system lost angular momentum and spiralled into one another somewhere in space 1.9bn to 2.9bn light years away from us. The loss of energy is radiated away as gravitational waves that ripple through spacetime to reach interferometer detectors on Earth.
Here's a simulation of the pair smashing into one another, with different wave forms being emitted by the cosmic collision.
[2]Youtube Video
“This big mass difference means that we can more precisely measure several properties of the system: its distance to us, the angle we look at it, and how fast the heavy black hole spins around its axis,” said Roberto Cotesta, a PhD student at the AEI.
It’s the first time that scientists have been able to estimate the precession of the black hole’s spins down to the first order, also known as the multipole moments.
“Thanks to the improved sensitivity, GW190412 has begun to reveal us a more diverse, submerged population, characterized by mass asymmetry as large as four and black holes spinning at about 40 per cent the possible maximum value allowed by general relativity,” said Alessandra Buonanno, director of the Astrophysical and Cosmological Relativity division at the AEI.
GW190412 is only the second confirmed gravitational wave signal from the third observation run that ended on March 27, this year. The researchers are now working their way through a backlog of 54 potential candidates. The first measurement from this batch - [3]GW190425 - was published in January and showed a collision that took place between two neutron stars. ®
Sponsored: [4]Legacy Modernization: Finding Your Way With Low-Code
[1] https://www.aei.mpg.de/2482444/a-signal-like-none-before
[2] https://www.youtube.com/watch?v=5AkT4bPk-00&feature=emb_title
[3] https://www.ligo.org/detections/GW190425.php
[4] https://go.theregister.co.uk/tl/1936/-8553/legacy-modernization-finding-your-way-with-low-code?td=wptl1936
Researchers working at the LIGO and Virgo, gravitational wave observatories in the US and Italy, confirmed their results this week, which is kind of unusual. Both detectors have become so sensitive that they sniffed a new candidate merger event about once every week between April 2019 to March 2020.
The confirmation of most gravitational wave measurements has become so common that they no longer make headlines. But the latest result - codenamed GW190412 - is particularly special, according to a team at the German Max Planck Institute for Gravitational Physics.
“For the very first time we have ‘heard’ in GW190412 the unmistakable gravitational-wave hum of a higher harmonic, similar to overtones of musical instruments,” [1]said Frank Ohme, leader of the Independent Max Planck Research Group “Binary Merger Observations and Numerical Relativity” at AEI.
“In systems with unequal masses like GW190412 – our first observation of this type – these overtones in the gravitational-wave signal are much louder than in our usual observations. This is why we couldn’t hear them before, but in GW190412, we finally can.”
The signals were emitted when the binary black hole system lost angular momentum and spiralled into one another somewhere in space 1.9bn to 2.9bn light years away from us. The loss of energy is radiated away as gravitational waves that ripple through spacetime to reach interferometer detectors on Earth.
Here's a simulation of the pair smashing into one another, with different wave forms being emitted by the cosmic collision.
[2]Youtube Video
“This big mass difference means that we can more precisely measure several properties of the system: its distance to us, the angle we look at it, and how fast the heavy black hole spins around its axis,” said Roberto Cotesta, a PhD student at the AEI.
It’s the first time that scientists have been able to estimate the precession of the black hole’s spins down to the first order, also known as the multipole moments.
“Thanks to the improved sensitivity, GW190412 has begun to reveal us a more diverse, submerged population, characterized by mass asymmetry as large as four and black holes spinning at about 40 per cent the possible maximum value allowed by general relativity,” said Alessandra Buonanno, director of the Astrophysical and Cosmological Relativity division at the AEI.
GW190412 is only the second confirmed gravitational wave signal from the third observation run that ended on March 27, this year. The researchers are now working their way through a backlog of 54 potential candidates. The first measurement from this batch - [3]GW190425 - was published in January and showed a collision that took place between two neutron stars. ®
Sponsored: [4]Legacy Modernization: Finding Your Way With Low-Code
[1] https://www.aei.mpg.de/2482444/a-signal-like-none-before
[2] https://www.youtube.com/watch?v=5AkT4bPk-00&feature=emb_title
[3] https://www.ligo.org/detections/GW190425.php
[4] https://go.theregister.co.uk/tl/1936/-8553/legacy-modernization-finding-your-way-with-low-code?td=wptl1936
A first but probably not the last
As the article points out, "The confirmation of most gravitational wave measurements has become so common that they no longer make headlines" (which, in a way, is sad). Thus this first observation of an asymmetrical collision is significant.
But it should be pointed out that the boffins expect this to be the first of many. Go, science!