Even small black holes emit gravitational waves when they collide, and LIGO heard them
LIGO scientists say they have discovered gravitational waves coming from another black hole merger, and it's the tiniest one they've ever seen.
The findings, submitted to the Astrophysical Journal Letters, could shed light on the diversity of the black hole population — and may help scientists figure out why larger black holes appear to behave a little differently from the smaller ones.
"Its mass makes it very interesting," said Salvatore Vitale, a data analyst and theorist with the LIGO Lab at MIT. The discovery, he added, "really starts populating more of this low-mass region that [until now] was quite empty."
The black holes had estimated masses of around 12 and 7 solar masses.
Related: LIGO May Have Detected Merging Neutron Stars for the First Time
First Joint Detection of Gravitational Waves by LIGO and Virgo
"Kilonova" Observed Using Gravitational Waves, Sparking Era of "Multimessenger Astrophysics"
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LIGO, the Laser Interferometer Gravitational-wave Observatory made physics history by managing to detect the previously elusive gravitational waves predicted by Einstein's Theory of General Relativity for the first time. They have, since they began operation, thrice observed the gravitational wave signatures emitted by the mergers of what are believed to be massive binary black hole systems. However, there is no confirmation of these events beyond the gravitational wave detection since black hole mergers may not emit anything else besides the gravitational waves. However, the merger of two neutron stars such as what is predicted to eventually happen to the Hulse–Taylor binary (which provided the first indirect confirmation of gravitational waves in the 1970s) will not only produce copious gravitational waves but possibly also a gamma ray burst or some other associated emission of electromagnetic radiation. The gravitational waves emitted by such an event would be weaker and harder for LIGO to detect, but on August 18th, noted astrophysicist J. Craig Wheeler tweeted a tantalising hint that they might actually have seen just such a thing happen:
New LIGO. Source with optical counterpart. Blow your sox off!
New Scientist reports that LIGO spokesperson David Shoemaker has not denied the rumour, and it seemed that four days after Wheeler's tweet the Hubble Space Telescope had been observing a neutron star binary candidate in the galaxy NGC 4993, which has since been deleted. From the article:
LIGO spokesperson David Shoemaker dodged confirming or denying the rumours, saying only "A very exciting O2 Observing run is drawing to a close August 25. We look forward to posting a top-level update at that time."
Speculation is focused on NGC 4993, a galaxy about 130 million light years away in the Hydra constellation. Within it, a pair of neutron stars are entwined in a deadly dance. While astronomers are staying silent on whether they are engaged in optical follow-ups to a potential gravitational wave detection, last night the Hubble Space Telescope turned its focus to a binary neutron star merger within the galaxy. A publicly available image of this merger was later deleted.
Further coverage and commentary from astrophysicist Ethan Siegel at Starts With A Bang.
For the first time three gravitational wave detectors have recorded the same event. The detection was made by both LIGO and Advanced Virgo (which has just recently begun collecting data for the first time). From the news release:
The LIGO Scientific Collaboration and the Virgo collaboration report the first joint detection of gravitational waves with both the LIGO and Virgo detectors. This is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector, and highlights the scientific potential of a three-detector network of gravitational-wave detectors.
The three-detector observation was made on August 14, 2017 at 10:30:43 UTC. The two Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, and funded by the National Science Foundation (NSF), and the Virgo detector, located near Pisa, Italy, detected a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes.
A paper about the event, known as GW170814, has been accepted for publication in the journal Physical Review Letters.
Scientists Witness Huge Cosmic Crash, Find Origins of Gold
It started in a galaxy called NGC 4993, seen from Earth in the Hydra constellation. Two neutron stars, collapsed cores of stars so dense that a teaspoon of their matter would weigh 1 billion tons, danced ever faster and closer together until they collided, said Carnegie Institution astronomer Maria Drout.
The crash, called a kilonova, generated a fierce burst of gamma rays and a gravitational wave, a faint ripple in the fabric of space and time, first theorized by Albert Einstein.
The signal arrived on Earth on Aug. 17 after traveling 130 million light-years. [...] The colliding stars spewed bright blue, super-hot debris that was dense and unstable. Some of it coalesced into heavy elements, like gold, platinum and uranium. Scientists had suspected neutron star collisions had enough power to create heavier elements, but weren't certain until they witnessed it. "We see the gold being formed," said Syracuse's Brown.
So the ring on your finger is actually the skeletal remains of neutron stars.
Observatories Across the World Announce Groundbreaking New Gravitational Wave Discovery
Today, physicists and astronomers around the world are announcing a whole new kind of gravitational wave signal at a National Science Foundation press conference in Washington, DC. But it's not just gravitational waves. That August day, x-ray telescopes, visible light, radio telescopes, and gamma-ray telescopes all spotted a flash, one consistent with a pair of neutron stars swirling together, colliding and coalescing into a black hole. The observation, called a "kilonova," simultaneously answered questions like "where did the heavy metal in our Universe come from" and "what causes some of the gamma-ray bursts scientists have observed since the 60s." It also posed new ones.
[...] All in all, the discovery marks an important milestone in gravitational wave astronomy and proof that LIGO and Virgo do more than spot colliding black holes. At present, the detectors are all receiving sensitivity upgrades. When they come back online, they may see other sources like some supernovae or maybe even a chorus of background gravitational waves from the most distant stellar collisions.
https://gizmodo.com/observatories-across-the-world-announce-groundbreaking-1819500578
[Also Covered By]:
- ESOcast 133: ESO Telescopes Observe First Light from Gravitational Wave Source
- In a First, Gravitational Waves Linked to Neutron Star Crash
- New gravitational wave discovery confirms dawn of a new field of astronomy
- What Have Gravitational-Wave Detectors Discovered?
- Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy (archive)
Papers:
Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger (open, DOI: 10.1038/nature24291) (DX)
Spectroscopic identification of r-process nucleosynthesis in a double neutron-star merger (open, DOI: 10.1038/nature24298) (DX)
A gravitational-wave standard siren measurement of the Hubble constant (open, DOI: 10.1038/nature24471) (DX)
The X-ray counterpart to the gravitational-wave event GW170817 (open, DOI: 10.1038/nature24290) (DX)
A kilonova as the electromagnetic counterpart to a gravitational-wave source (open, DOI: 10.1038/nature24303) (DX)
Origin of the heavy elements in binary neutron-star mergers from a gravitational-wave event (open, DOI: 10.1038/nature24453) (DX)
Multi-messenger Observations of a Binary Neutron Star Merger (open, DOI: 10.3847/2041-8213/aa91c9) (DX)
Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A (open, DOI: 10.3847/2041-8213/aa920c) (DX)
An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A (open, DOI: 10.3847/2041-8213/aa8f41) (DX)
INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational-wave Event GW170817 (open, DOI: 10.3847/2041-8213/aa8f94) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Discovery of the Optical Counterpart Using the Dark Energy Camera (open, DOI: 10.3847/2041-8213/aa9059) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models (open, DOI: 10.3847/2041-8213/aa8fc7) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta (open, DOI: 10.3847/2041-8213/aa9029) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South (open, DOI: 10.3847/2041-8213/aa905c) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. V. Rising X-Ray Emission from an Off-axis Jet (open, DOI: 10.3847/2041-8213/aa9057) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta (open, DOI: 10.3847/2041-8213/aa905d) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale (open, DOI: 10.3847/2041-8213/aa9055) (DX)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts (open, DOI: 10.3847/2041-8213/aa9018) (DX)
The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck (open, DOI: 10.3847/2041-8213/aa8edf) (DX)
A Deep Chandra X-Ray Study of Neutron Star Coalescence GW170817 (open, DOI: 10.3847/2041-8213/aa8ede) (DX)
The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source (open, DOI: 10.3847/2041-8213/aa905e) (DX)
The Emergence of a Lanthanide-rich Kilonova Following the Merger of Two Neutron Stars (open, DOI: 10.3847/2041-8213/aa90b6) (DX)
Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration (open, DOI: 10.3847/2041-8213/aa9060) (DX)
The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source (open, DOI: 10.3847/2041-8213/aa9116) (DX)
The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817 (open, DOI: 10.3847/2041-8213/aa9110) (DX)
The Rapid Reddening and Featureless Optical Spectra of the Optical Counterpart of GW170817, AT 2017gfo, during the First Four Days (open, DOI: 10.3847/2041-8213/aa9111) (DX)
Optical Follow-up of Gravitational-wave Events with Las Cumbres Observatory (open, DOI: 10.3847/2041-8213/aa910f) (DX)
A Neutron Star Binary Merger Model for GW170817/GRB 170817A/SSS17a (open, DOI: 10.3847/2041-8213/aa91b3) (DX)
Previously: European Southern Observatory to Announce "Unprecedented Discovery" on Monday
Original Submission #1 Original Submission #2 Original Submission #3
An 'unknown' burst of gravitational waves just lit up Earth's detectors:
Earth's gravitational wave observatories -- which hunt for ripples in the fabric of space-time -- just picked up something weird. The Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo detectors recorded an unknown or unanticipated "burst" of gravitational waves on Jan. 14.
The gravitational waves we've detected so far usually relate to extreme cosmic events, like two black holes colliding or neutron stars finally merging after being caught in a death spiral. Burst gravitational waves have not been detected before and scientists hypothesize they may be linked to phenomena such as supernova or gamma ray bursts, producing a tiny "pop" when detected by the observatories.
This unanticipated burst has been dubbed, for now, S200114f, and was detected by the software that helped confirm the first detection of gravitational waves.
[...] Astronomers have already swung their telescopes to the interesting portion of the sky, listening in across different wavelengths of the electromagnetic spectrum for a whisper of what might have occurred.
Previously:
LIGO Observes Lower Mass Black Hole Collision
First Joint Detection of Gravitational Waves by LIGO and Virgo
LIGO May Have Detected Merging Neutron Stars for the First Time
GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2
Europe's "Virgo" Gravitational Wave Detector Suffers From "Microcracks"
LIGO Black Hole Echoes Hint at General-Relativity Breakdown
LIGO Data Probes Where General Relativity Might Break Down
Did the LIGO Gravitational Wave Detector Find Dark Matter?
Second Detection of Gravitational Waves Announced by LIGO
(Score: 1) by anubi on Monday November 20 2017, @07:46AM (11 children)
Seems with as small as black holes are in relation to their mass, unless their collision trajectories are dead-on, seems like they oughta just go into a wild spin-fit with each other - marriage by proximity with their strong gravitational field.
Will a black hole explode if it is spun up too much?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by takyon on Monday November 20 2017, @08:07AM (3 children)
I believe they tend to orbit each other for a long time before colliding, same as with that famous neutron star pair measured on Aug. 17.
Black holes can't really explode since all the stuff can't escape the event horizon, although matter and gas in the accretion disc surrounding the black hole can undergo some violent changes.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by anubi on Monday November 20 2017, @09:38AM (2 children)
Just curious if tangentially incoming matter would spin the thing up so much that centrifugal force would sling the innards of the black hole to the other side of the event horizon, in which case I would think it would spew subatomic particles in a radial pattern along its "equator" - in much the same manner as a centrifugal spinning water sprinkler spews water droplets.
I have often thought that its the rotational inertia of the universe that may make it "eternal", in the sense that if any black hole tried to gobble the whole thing up, it would be swallowed and re-emitted as sprays of subatomic particles, which re-initiates the whole coalesced hydrogen-star birth cycle. How the entropy resets is a whole new can of worms for me, with theological explanations seeming to be the best answer.
Do we really know the size of the universe, or are we still constrained by the word "observable"? Did this whole universe start with the "big bang", or is the part that did ( our observable universe ), a part of even a larger universe which we do not see with our present technology? I guess what I am having a hard time with is does the universe have a starting and an ending time, or is it infinite, with "local universes" such as the one we observe - winking in and out of existence like some sort of relaxation oscillator?
I guess no one knows, but as we build better and more sensitive sensors, we seem to make two new questions for every answer we seek.
As a kid of the 50's, I thought we were on the edge of knowing it all. Everything was made out of atoms. We could even count them. They went together like tinker-toys to build everything. Once we figure out how to put these atoms together, there was no limit to what we could make. Even life itself was a collection of atoms in the right order. I was little more than a really fancily designed radio thingie. And told God made me. Out of atoms. Or dust, which is made from atoms.
Now, as an old man, I feel so much dumber. Nowhere near as close to intellectual nirvana that I had as a kid. All I seemed to discover is how little I really know. This new quantum stuff really blows me away. So does the sheer complexity of DNA, and how cleverly assembled are the chemical structures and reactions that we call "life".
Despite the fact I can now design and program my own computers, when as a kid, I was totally fascinated with a mechanical adding machine. I feel a heckuva lot dumber today than I did 50 years ago.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by FatPhil on Monday November 20 2017, @09:57AM (1 child)
PBS SpaceTime covered this here: https://www.youtube.com/watch?v=KePNhUJ2reI but you'll probably need the intro ones too.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday November 21 2017, @04:32AM
In other words, "black hole" is the same thing as "edge of the universe".
(Score: 3, Interesting) by edIII on Monday November 20 2017, @08:17AM (5 children)
They do go into a "spin-fit" with each other. At some point though, while spinning furiously, they do eventually touch. Hence, the term collide. A straight up head on collision seems extremely unlikely, but if the universe is indeed infinite according to some theories, they do occur.
I remember in reading the last LIGO papers they used a term "ring down". If a quarter was spinning on your desk, eventually it will (excepting those times when it stands on its edge) start to fall over and start rotating on the edges, faster and faster, till the surface of the quarter is finally flat against the surface. The ring down is that end when the black holes actually collide and merge together. If you listen to the quarter, that's similar to what the scientists are doing listening to the black holes circle each other.
Hoping one of our other posters more well versed in the matter chime in, and explain it better.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 3, Informative) by FatPhil on Monday November 20 2017, @09:36AM (1 child)
https://www.youtube.com/watch?v=gtZ7OVoI2nc
https://www.youtube.com/watch?v=kL81uuYW9BY
But it's worth just subscribing, they cover a whole host of things: https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g/featured?disable_polymer=1
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 1) by anubi on Monday November 20 2017, @10:17AM
Thanks for the links. I watched your last one first.. intriguing.. they have the same belief I have about EM drives and "energy from the vacuum", but I do not understand the underlying physics, rather I am merely conjecturing using previous observations as basis.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 3, Informative) by FatPhil on Monday November 20 2017, @09:41AM (2 children)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 1) by anubi on Monday November 20 2017, @10:31AM
Thanks... I was looking for what would provide the "resistance" to slow it down. I was envisioning a barbell-shaped mass spending an eternity in a high speed spin with nothing to slow it down. I never considered the energy needed to create gravitational waves.
I considered "tidal" fields, as in how the earth and moon interact through gravity, with the earth gradually slowing down as it transfers its rotational inertia to the moon, slinging it further and further out. But I saw no nearby thing to transfer the energy to.
Just because it isn't nearby does not mean its not there. Those gravitational waves go on to infinity, I suppose, giving infinitesimally small ( but non-zero ) drag on the rotating pair.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2) by edIII on Monday November 20 2017, @11:31PM
Thanks. I always appreciate the explanations from you guys :)
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 3, Interesting) by stormwyrm on Monday November 20 2017, @12:53PM
Numquam ponenda est pluralitas sine necessitate.