![]() ![]() “When updating my lecture on gravitational-wave astronomy, I realized that the gravitational-wave observatories had found first hints of an absence of chirp masses and an overabundance at exactly the universal masses predicted by our models”, says Fabian Schneider. ![]() In merging black holes, the universal black-hole masses of approximately 9 and 16 solar masses logically imply universal chirp masses, i.e. The gap in chirp masses at 10–12 solar masses and the so-far identified features at about 8, 14, 27 and 45 solar masses are indicated. The top panel shows the raw data and probability distributions of the chirp masses of each individual event while the bottom panel shows a model inferred from the combined observations. The HITS team could now show that – regardless of the chemical composition – stars that become envelope-stripped in close binaries form black holes of 16 solar masses but almost none in between.įigure 3: Distribution of the chirp masses of all binary black-hole mergers observed today. This is a direct consequence of these black holes originating from stars born with a chemical composition different from that in our Milky Way Galaxy. ![]() Not in our galaxy: Black holes with much larger massesĮver since the first discovery of merging black holes, it became evident that there are black holes with much larger masses than the ones found in our Milky Way. “Any features in the distributions of black-hole and chirp masses can tell us a great deal about how these objects have formed”, says Eva Laplace, the study’s third author. These features correspond to the universal chirps predicted by the HITS team. In particular, there seems to be a gap in the distribution of the chirp masses of merging binary black holes, and evidence emerges for the existence of peaks at roughly 8 and 14 solar masses (Figure 3, see below). The “stellar graveyard” (Figure 2) – a collection of all known masses of the neutron-star and black-hole remains of massive stars – is quickly growing thanks to the ever-increasing sensitivity of the gravitational-wave detectors and ongoing searches for such objects. Visualization credits: LIGO-Virgo-KAGRA / Aaron Geller / Northwestern. Arrows connect two merging compact objects and their merged remnant as seen by gravitational-wave emissions. The figure shows inferred gravitational masses of neutron stars and black holes from electromagnetic (EM) and gravitational-wave observations (LIGO-Virgo-KAGRA). “Severe consequences for the final fates of stars”įigure 2: Masses in the stellar graveyard (in units of solar mass). “The existence of universal chirp masses not only tells us how black holes form”, says Fabian Schneider, who led the study at HITS, “it can also be used to infer which stars explode in supernovae.” Apart from that it provides insights into the supernova mechanism, uncertain nuclear and stellar physics, and provides a new way for scientists to measure the accelerated cosmological expansion of the Universe. The team’s models, however, suggest that some black holes come in standard masses that then result in universal chirps. So far, it has been assumed that the merging black holes can have any mass. ![]() From observing this frequency evolution (the chirp), scientists can infer the so-called “chirp mass”, a mathematical combination of the two individual black hole masses. When two stellar-mass black holes merge, they emit gravitational waves of increasing frequency, the so-called chirp signal, that can be “heard” on Earth (see Movie). The discovery of gravitational waves in 2015 – already postulated by Einstein one hundred years ago – led to the 2017 Nobel Prize in Physics and initiated the dawn of gravitational-wave astronomy. Image credit: Deborah Ferguson, Karan Jani, Deirdre Shoemaker, Pablo Laguna, Georgia Tech, MAYA Collaboration. Ripples in the spacetime around a merging binary black-hole system from a numerical relativity simulation. Klaus Tschira Guest Professorship Program.Scientific Databases and Visualization (SDBV).Machine Learning and Artificial Intelligence (MLI).Data Mining and Uncertainty Quantification (DMQ).Computational Molecular Evolution (CME).The Universal Sound of Black Holes - HITS × ![]()
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