Scientists Detect 'Unknown or Unanticipated' Burst of Gravitational Waves In Space

iONiUM writes: LIGO has detected gravitational waves deep in space. The source is currently unknown.

The Independent reports: "Scientists think they have detected an 'unknown or unanticipated' burst of gravitational waves coming from somewhere deep in space. The wobble in spacetime was picked up unexpectedly by the LIGO experiment, which was specifically built to detect gravitational waves. Astronomers have a picture of what part of the sky the burst originated from, and will look to find more information about its source by further studying the area. But for now there is very little indication of what could have caused the blast, which sent ripples through the fabric of the universe that were detected by LIGO in recent hours. Errors of this kind are predicted to happen only once every 25 years, indicating that the burst probably did really come from an astrophysical event."

In case anyone is worried, it's already been confirmed Betelgeuse is still there.

Your mom

[tezbobobo]

This is going to inspire a lot of 'your mom' jokes.

Re:Your mom

[Layzej]

In case anyone is worried, it's already been confirmed Betelgeuse is still there.

Aldebaran's great, okay, Algol's pretty neat, Betelgeuse's pretty girls, Will knock you off your feet. They'll do anything you like Real fast and then real slow, But if you have to take me apart to get me there Then I don't want to go.

Betelgeuse

[Rei]

In case anyone is worried, it's already been confirmed Betelgeuse is still there.

> ... was still there, as of around 700 years ago. ;)

Re:Betelgeuse

[NoNonAlphaCharsHere]

Actually, it's an emission from Betelgeuse's binary, Burritogeuse.

Re:

[avandesande]

I thought burritojuice was something found running down your arm

Re:

[guruevi]

In humans it's called a leg. And it typically only happens after eating Taco Bell.

Re:Betelgeuse

[U0K]

True, due to the distance we can't say with a high degree of certainty that it is still there right now.

But keep in mind that gravitational waves propagate at the same velocity as light does.
Hence if we can observe Betelgeuse in the EM spectrum unchanged, it's reasonable to assume that whatever caused this reading of a burst of gravitational waves also wasn't Betelgeuse.

Re: Betelgeuse

[John Trumpian]

No. Gravitational waves tend to travel faster then the light in this case. While light is in fact a wave too, the light is behing hinderd by gas and other 'pollution'. Gravitational waves are not hindered by this. So yes, in a complete clean & vacuum space gravitational waves travel faster then light. Betelgeuse might be blown already..

Re: Betelgeuse

[John Trumpian]

Correction: So yes, in a complete clean & vacuum space gravitational waves travel not faster then light. In this case they might. For all we know Betelgeuse might be blown already..

Re:

[cusco]

How much of a difference would that make over only 700 light years? Just curious, as I have no clue how to figure that out myself.

Re: Betelgeuse

[fazig]

Using very simple math, we can take the refractive index.
But since I do not know the refractive index of the interstellar medium I'll use that of air here on Earth as an example: n = 1.0003
And here our atmosphere is much denser than the interstellar medium. Disregarding the effects of wavelength the calculation is very simple as the refractive index is calculated as n = c / v. Solved for v = c / n, which means that it will take light 1.0003 times longer to travel through air than a perfect vacuum.

Now if the interstellar medium was air those 700 years for gravitational waves would be 700.21 years for light. A 77 day difference, which translated into the interstellar medium should be magnitudes lower than that.

Re: Betelgeuse

[John Trumpian]

Can be weeks or months. Since we not know p, = polution, in the equation it will always be a wild guess. Light will be bend by gravity, read electric magnetism, gravitational waves might be not or not as much under the influence of such magnetisme. But I think it is bold to state it was not Betelgeuse based on the fact how fast light travels. It is not very obvious it is Betelgeuse but who knows..

Re:

[iikkakeranen]

Betelgeuse is only 700 lightyears away. The difference between the arrival time of gravitational waves and visible light would be very small, possibly impossible to measure because of the size of the star. Light takes more time just to travel from the star's core to its surface, so any lag effect caused by the density of interstellar medium would be hard to separate from the expected visual delay. You can get meaningful differences of multiple hours if the event is in a distant galaxy, but as for local even

Re: Betelgeuse

[John Trumpian]

I would argue that. Light can be easily blocked, this also explains the sudden diming of the star. 700 lightyears is still a long way..

Re:

[iikkakeranen]

You're seriously overestimating the effect. We've had measurements from events hundreds of millions of light years away where the difference between gravitational waves and light arriving was a few seconds. At 700ly we'd be looking at microseconds!

With the size of the star, the interaction with the stellar material is going to be far more significant than that (even the error bars we have for the star's size are bigger). It may take a few hours from the core collapse to visible effects. We'd be detecting ne

Re: Betelgeuse

[John Trumpian]

I agree with your statement. I was merely denying that gravitational waves travel with the same speed as light .they so not. Now light has a spectrum. Ultraviolet light has a much longer wavelength so it will in most cases not be blocked. We still do not know a lot about particles light and how they behave is the lightspeed a constant? Is lightspeed the fasted speed? So many questions need to be proper answered...

Re:

[Zorpheus]

I think it's not about the 700 light years, it's about the star itself. If something happens in its core the gravitational waves leave the star at the speed of light. But a visible effect is slowed down by the star itself. It takes a bit until the explosion reaches the outside.

Re:

[ZoomieDood]

Any possibility we're seeing a gravitational doppler shift with bodies orbiting one another at a high speed? Wouldn't it be possible we're sensing a "compression" of gravitational waves as one body orbits the other, with it's "front face" towards us, and as it orbits around to the other side, it "elongates" before temporarily "disappearing" when it goes behind the other?

To us, it might appear to be a "flickering" of gravitational waves.

What's the period associated with the "wobble"?

Re:

[Mal-2]

NO.

When LIGO picked up merging neutron stars, the EM component followed within three or four seconds, from hundreds of millions of light years away. Had Betelgeuse been the source, it would have been evident within minutes to hours. Nothing significant happened there, from our perspective. It still hasn't.

Re:

[RockDoctor]

Is Betelgeuse anything like large enough to create measurable GWs, even if it were to go directly to a black hole? With a mass of 11 ("+5 -3", i.e. range 8-16) solar masses, whether it's fusing core is large enough to exceed the Chandrasekhar limit is ... a good question. The internal structure of large stars is complex, and well buried. In particular, how much of their outer shell is stirred into the core (and how much of the core material, contaminated with fusion products is stirred back out into the env

Warp drive of course! /s

[wierd_w]

Ever looked at the calculations for an Alcubierre drive?

OFF THE CHARTS.

Clearly, this was an alien FTL test!

(sarcasm, in case anyone wondered.)

Clearly it is Climate Change

[Anonymous Coward]

Climate Change is causing errors in the instrument, obviously.

Stuff happens, people react

[AndyKron]

Maybe their Arduino glitched?

dropped

[jmccue]

mother: stop dropping your universe

kid: but maaaa

mother: you know that upsets the animals. Do that again I will take it away

kid: ooh Kay

Why new observation systems are important

[JoshuaZ]

This shows a major part of why new methods of observation are important. It isn't just about using them to study things we already know about, but also to discover completely new phenomena that we had no guess were a thing.

Re:

[Dunbal]

Why? You're just going to invent a new particle to explain it.

Re:

[UnknowingFool]

Unobtaniatron. Dibs!

FTL

[jellomizer]

Any astrophysicist out there who has a good estimate on a gravitational wave that would be given on a ship that would need to bend space time for Faster Then Light travel?

Re:

[Anonymous Coward]

i think you need a sci-fi author for that
he could also explain the difference between then and than to you

Re:

[Culture20]

[...] he could also explain the difference between then and than to you

That's what editors are for.

Re:

[RockDoctor]

That's what editors are for.

That's an author's job. Subbies (sub-editors) check things like English usage, conforming to the publication's style guide, correctly spelling foreign names, terminating lists consistently (as I've just had to do) etc. That job has disappeared now - it is relegated to Clippy, or just not done at all as being too expensive for modern publishing (particularly "news-like" publishing). Then the editor chooses which items are put onto the page, which are sent back for expansion or co

Re:FTL

[lkjlkjlkj]

You mean with e.g. an Alcubierre drive? [wikipedia.org] Let us suppose that such a drive were possible. It would still need to be powered by some energy source. We can estimate the amount of energy required by a warp drive so that the LIGO experimenters wouldn't be able to tell if it were a spaceship or a collision. Back in 2015 [slashdot.org], LIGO detected a gravity wave event with the following relevant back-of-the-envelope characteristics: "one billion light years from earth" and also "the coalescence converted about three times the mass of the Sun (or nearly six million trillion trillion kilograms) into gravitational-wave energy, most of it emitted in a fraction of a second. By contrast the Sun converts a mere two billionths of one trillionth of its mass into electromagnetic radiation every second"
Assuming that "fraction of a second" means, say, 100ms, the power output of the collision was about 30 SunMass/s, whereas the power output of the Sun is 2x10^-21 SunMass/s. Let's back-of-the-envelope these numbers to 1x10^1 SunMass/s and 1x10^-21 SunMass/s respectively. This means that the collision put out 1x10^22 SunPower. This amount of power was detectable by LIGO at a distance of 1x10^9 light years ~ 1x10^22km.
We want the formula relating power output and distance to source that gives the same power by the time it gets to LIGO. The power of a wave in 3-space decreases as the square of the distance. So, the power by the time the graavity waves get to LIGO was proportional to p/d^2, where p is the power at source, and d is the distance to LIGO. Setting that to be equal for the warp drive and the black-hole collision (so that they are "indistinguishable" by LIGO), we find that for the warp drive to be detectable, it would need p/d^2 = 1x10^-22 SunPower per km^2. Plugging in various values, we can get some benchmarks that might give one an idea of how god-like the ship owners would need to be.
Suppose that the ship could pump out one full SunPower (!!!!). We would be able to detect this event at 1x10^11km or closer. This is about 100 times the size of the solar system or so, but the nearest star is billions of times further away. In other words, if we were to detect such a ship with LIGO, it was almost certainly here to see us, and nobody else. Suppose that the ship was inside of geo-stationary orbit, say 1x10^4 km or so. Then the ship would "only" need to pump out 1x10^-16 SunPower to be detectable. To convert this to meaningful units, we need this wikipedia list [wikipedia.org] which suggests that 1x10^-16 SunPower ~ 1x10^10 Watts. By the same list, this is comparable to fissioning a gram of U235 in a second. This is about 1/20 of the rate at which a "normal" nuclear reactor [nuclear-power.net] consumes fuel. Assuming this spaceman was able to device a warp drive, this seems a reasonable quantity of power production.
tl;dr; It could happen, and if so, they're here to spy on us.

Re:

[lkjlkjlkj]

That "back in 2015" LIGO link should be https://www.ligo.org/science/P... [ligo.org]

Re:

[cusco]

This is why I keep coming back to SlashDot after all these years.

Grams fissioned per second

[GPS Pilot]

this is comparable to fissioning a gram of U235 in a second. This is about 1/20 of the rate at which a "normal" nuclear reactor consumes fuel.

Your source says a reactor consumes 1005 kg of fissile material per year, or 0.03186 grams per second.

So one gram per second would be 31 times the rate of the reactor, right?

black hole collision

[avandesande]

I know it's statistically unlikely but what happens when two black holes collide directly? IE not orbiting each other.

Re:

[OldBus]

The folks who run the detectors have announced previously that they have detected the collision of black holes, so presumably the signal they've got doesn't look like that (or anything else they had been expecting to see)

Re:

[UnknowingFool]

LIGO was built for the purpose of detecting collisions of stars and black holes and has detected both before. I assume that if the scientists say this is unknown to them, it does not fit under the parameters of black hole collisions. Now it could still be a black hole collision and scientists have to revise their parameters.

Re:

[avandesande]

Previous discoveries are binary pairs that collide as their orbit decreases due to energy lost to gravity waves and has a distinct signature. I am talking about two dissociated black holes colliding as a result of two galaxies merging or something like that. The gravity waves would be completely different.

Re:

[UnknowingFool]

The signal that is measured is the merging of two large masses. The characteristic that is not that they must be binary pairs. What you seem to suggest is that two black holes coincidently be headed for each other in an exact trajectory? That would be highly unlikely.

Re:

[avandesande]

Yeah, that's what I said, unlikely. But what do we know about interstellar collisions? Has anyone modeled or calculated probabilities? Oumuamua wasn't that far off from hitting the sun.

Re:

[UnknowingFool]

I would say extremely unlikely. Most large masses merge slowly over millennium in what I describe as a slow dance. Also most of the really large black holes are in the centers of galaxies and not likely to collide like this. The rest are relatively stationary to their galaxy. Of the many known black holes, only 1 is known to be a runaway not connected to any galaxy.

Re:

[RockDoctor]

LIGO was built for the purpose of detecting collisions of stars and black holes

False.

LIGO (like the 3 or 4 generations of previous gravity wave detectors) was built to detect gravity waves, of any strength, from any source. Since the field was conceived in the early 1960s, each generation of detector was insufficient to clearly detect any gravity waves, so the next generation took the funding and technology as much further as they could afford to, in the effort to detect gravity waves of any sort. (Coincid

Re:

[UnknowingFool]

Gravity waves of “any strength”? Are you sure about that considering gravity waves ripple each and every time two bodies orbit each other. Like the Earth and the Moon. Or are these detectors designed to ignore those minor waves for very large ones that occur with collisions?

Re:

[RockDoctor]

Almost certainly our current GW detectors are already responding to (say) primordial GWs from the Big Bang ; quite possibly Weber's aluminium bars in the 1960s were. The issue is, the noise level in the sensors, in the frequency ranges that (say) primordial GWs have their highest power, is too high. That has got nothing to do with the physics of GWs, but of electronics, of the stiffness of the ground, of seismic noise. Getting away from ground noise is one of the major justifications for proposing LISA - th

Re:

[UnknowingFool]

You missed my whole point: while the instruments used in LIGO are sensitive to detect small gravity waves, LIGO as a whole was designed to look for larger collisions associated with massive collisions like two black hole or two neutron stars as there is a lot of unwanted signals. Many systems like radar systems can tuned to detect smaller signals; it is pointless to the purpose to do so. An airport’s radar could probably detect the movement of birds for several hundred miles but that would cause so mu

Re:

[RockDoctor]

They're considerably more likely (and appear more frequently in the data stream form the GWOs) than "NSBH" mergers, or indeed "NSNS" mergers.

Neutron stars have a lower mass limit of about 1.4 solar masses - the Chandrasekhar limit [wikipedia.org] needed to overcome electron degeneracy pressure. I've never heard a method for reducing the mass of a neutron star. They have an upper mass limit - neutron degeneracy pressure plus a (less certain) amout of nucleus-nucleus repulsion pressure. Theorists differ, putting the upper l

Somebody near the detector sneezed?

[SlideRuleGuy]

And is too embarrassed to fess up?

Re:Somebody near the detector sneezed?

[Roger W Moore]

There are two LIGO detectors: one in Washington state and the other in Louisiana and they look for coincidences between the detectors so it would have to be one hell of a sneeze.

Re:

[RockDoctor]

Plus one in Italy, and another coming online in Japan. (At this moment, the Italian one is flagged as having been down for maintenance for 3h45m, and the Japanese one is just "down" for no given reason.)

People have known about the problem of stochastic local noise since the early decades of last century when seismographs were developed. Techniques for managing such noise were coming in before WW2, as the measurement moved from ink-on-paper to electronic detectors.

Discarding local noise by using multiple s

In a galaxy far away

[gillbates]

Alderaan is no more. Science is just now learning what prophet Lucas told us years ago.

Re:In a galaxy far away

[UnknowingFool]

That’s plain silly. If you’ve attended any meetings at the local planning commission in Alpha Centauri for the last 50 years, you’d know it was a scheduled demolition by the Vogons. That’s if you bothered to take interest in local affairs.

Disturbance in force

[Perl-Pusher]

So they detected a disturbance in the cosmic force that binds everything?

Too paywalled...

[JoeDuncan]

...didn't read. Got a good link?

Re:

[JoeDuncan]

That IS a good Link! thx

Re:

[RockDoctor]

Go to the "Gravitational Wave Open Science Center [gw-openscience.org] and access the "Chirp" website (also available as an app for Android and that Apple thing) ; you'll get the most recent alert, access to the GRACEdb database of GW observation alerts, and (from the apps, but not the website) the current engineering status of the detectors.

If you use one of the apps, about 3 times a week you'll get a "chirp" on your phone to alert you to a signal having been detected. The pipeline is 5 to ten minutes long - obviously, no hum

Re:

[UnknowingFool]

I think the unanticipated refers to the characteristics of the burst. If it was a black hole or neutron star collision, it would appear different in the data. Thus it is unknown to them what may have caused it.

Re:

[Aighearach]

That's how silly it is to report this in the media this soon, it isn't even clear if they meant what they said or if they were using casual language.

Which noun exactly was unanticipated? Unclear.

Re:

[UnknowingFool]

When would you report it? Six months from now when it wouldn’t be really news for nerds. That would be more of a journal entry. Also way less exciting: “Scientists six months ago found a signal that they can explain now.”

Re:

[Aighearach]

If it isn't still news after [the amount of time you need to know what the fuck you even think you saw] then it was never news, and isn't news, and was just vapid blathering.

When an actual new thing happens, "this individual was surprised" is not actually the story.

Re:

[UnknowingFool]

You do understand that they could report when they find something AND report later when they have more explanation. Your idea of news is missing the key aspect of timeliness. The story here is “we think we have something new and exciting”. It could be error; it could be groundbreaking.

Re:

[Aighearach]

Timeliness doesn't happen until you know if it is news. By definition.

Currently it is gossip they're spreading. As you well know; "It could be error; it could be groundbreaking"

Re:

[UnknowingFool]

By your logic, they should wait to report on this years, maybe decades from now. A newspaper should never report that a body was found yesterday until someone is convicted at trial of murder. Also you really need to look up what gossip is. One scientist didn’t call another scientist “far and ugly” for dating Chad.

Re:

[Aighearach]

No, they should wait until they have something to report, instead of reporting when they feel emotions of excitement.

That's all that happened! Some people got excited at work! They didn't complete any work yet though. Finish a stage of work, report on the stage that was completed. That's the part you know about.

Re:

[UnknowingFool]

No, they should wait until they have something to report, instead of reporting when they feel emotions of excitement.

You do know that this is a signal that the top scientists in the field don’t know for sure what it is right? This isn’t some high school science experiment. By “something to report” you mean to say that you don’t find it significant thus overriding the expertise of experts.

That's all that happened! Some people got excited at work!

You seem to have a lack of understanding of what gossip and facts are. No one is talking about tumors about two scientists dating. They are talking about actual data, actual facts. People in the field getting

Re:

[Aighearach]

You seem to have a lack of understanding of what gossip and facts are.

You seem to lack an understanding of the meaning of the words I used.

What the hell are you talking about?

If you're not sure, you don't yet know if you think I'm wrong.

Re:

[UnknowingFool]

You said: “Currently it is gossip they're spreading.” The meaning of gossip [dictionary.com]

idle talk or rumor, especially about the personal or private affairs of others

You equated scientific discovery backed by data to rumor. You may not care about the discovery; that does not make gossip. Please use the dictionary.

If you're not sure, you don't yet know if you think I'm wrong.

I know what I’m talking about. I’m specifically pointing out that you don’t know what the hell you are talking about. You basically said people who are publishing a paper haven’t finished yet. You haven’t read the paper. You don’t know th

Re:

[Aighearach]

You equated scientific discovery backed by data to rumor.

This is literally the danger of announcing now; people like you get confused into thinking a discovery happened!

Between your eyes and your mouth, it became rumor.

Re:

[UnknowingFool]

This is literally the danger of announcing now;

And what do you propose the alternative is? Never announcing any potentially breakthroughs until decades after it happened? You do understand withholding data is not the norm of science? For example there are some candidate signals from SETI that could still be signals of intelligent life that have not been ruled out as being caused by natural phenomena. And they may never be ruled out until maybe man gets the ability to visit the signal location in some possible future.

people like you get confused into thinking a discovery happened!

Something did happen. You keep denyin

Re:

[Aighearach]

Already lost the thread, eh?

If you get confused, you could always re-read it.

Re:

[UnknowingFool]

Please scroll up and read. Also please consult a dictionary as you keep calling data backed science as rumor and gossip. This entire thread is because you don't think something should be reported. You feel that someone you should dictate to others what is news and what isn't news. You don't think that researchers have completed their work when you haven't read it yet. You think because we can't explain something that it must never have happened. The world is bigger than you.

What date of event are they referring to?

[ebyrob]

The LIDO website mentions an event back on January 6,but that was already explained by 2 neutron stars colliding. They also don't mention anything about Orion or Betelgeuse. Where are these guys getting their information, and even what information was it, very thin on details.

Re:

[RockDoctor]

See the link I posted a short while ago. Short version : the automated pipeline handling 2, 3 or 4 GW observatories can churn out a 90-95% contour (1 to 2 sigma) for "source within this region" from the relative timing and intensity at 2, 3, 4 observatories. It may have escaped your notice, but there are atlases plotting where stars are on the sky. Putting the two together can strongly exclude a lot of potential sources, to varying levels depending on the probability contours for the source detection.

(I ha

Neutrinos

[monkeyman.kix]

Pretty sure I saw on twitter (really reliable source for science news) that there was a spike in neutrino emissions. Wonder if they are correlated.

Re:

[RockDoctor]

The various HECR (about half a dozen observatories), neutrino observatories (6 or so, some coming on line), gamma-ray and X-ray telescopes (I've lost count) and a number of others are working on an automated, low-false-positive pipeline for combining their data. The basic topology is derived from the GCN system used for a decade and a half for gamma-ray bursts and their automated follow up (within, literally, seconds of observation). The problem is that you'll be getting hundreds of reports a day, and the f

WTF?

[fredrated]

From deep in space? Unanticipated? Doesn't that describe all gravitational waves?

Jump Drive

[Chronus1326]

It was a Jump Drive. Colonial made.

Hahahahahaa!!!

[Anonymous Crowded]

They're back.

Later suckers, I'm going home.

Betelgeuse

[kbahey]

It is unlikely that Betelgeuse is about to blow up.

Here is why: Betelgeuse has 3 components to its light curve: a 180 day cycle, a 425 day one, and a third at 5.9 years.

It just so happens that "the current faintness of Betelgeuse appears to arise from the coincidence of the star being near the minimum light of the ~5.9-yr light-cycle as well as near, the deeper than usual, minimum of the ~425-d period.".

So two minima overlapped, and we get Betelgeuse fainter than any time in recorded history.

See this Astronomical Telegram [astronomerstelegram.org], and the light curve from AAVSO [skyandtelescope.com].

Re:

[RockDoctor]

So two minima overlapped, and we get Betelgeuse fainter than any time in recorded history.

Actually, it is as faint as it has ever been, but not fainter. The first instrumental records are at about this level, and the first optical records (1840-odd, with comparison against other nearby stars) may indicate a deeper dimming then, and possibly another in the 1860s or so.

It is unusual ; it isn't unprecedented, even for Betelgeuse alone. Looking further out at other high mass stars, they're pretty much all vari

Extraordinary claims require ...

[Alwin Barni]

The linked article does not provide any references except a twitter, additionally the use of phrases such as "unknown or unanticipated", "picked up unexpectedly by the LIGO" (as all such events by their nature are unanticipated) make me very skeptical regarding this revelation, which seems to be purposely over-hyped.
Additionally I have not found anything of this nature on other science services, except one mention of newly detected merger of a neutron start and a black hole, and one event which was registe

Re:

[epine]

This story is beyond fail. Normal LIGO detection is driven by pattern matching against predicted collapse waveforms from established theory. The specificity of the detection patterns boosts sensitivity, though if you go too far in this direction, you run the risk of detecting patterns as a direct byproduct of looking too hard.

A signal found by general-purpose "anomaly" algorithms is a different animal. How do you define anomaly? How do you distinguish a worst-case scenario in your noise cancellation (aka a

Re:

[Alwin Barni]

Thank you, just found some more detailed article about the event: https://www.cnet.com/news/an-u... [cnet.com]

Re:Extraordinary claims require ...

[ChumpusRex2003]

The primary reference for this low latency alert is: https://gracedb.ligo.org/super... [ligo.org] Preliminary reports of GW detection from the low-latency pipelines are published online ( https://gracedb.ligo.org/lates... [ligo.org] ), and via e-mail circulars ( https://gcn.gsfc.nasa.gov/gcn3... [nasa.gov] )

The normal low-latency search process at the LIGO/VIRGO observatories is to attempt to match received signals with a library of pre-calculated models. In other words, the emission of gravitational waves from a variety of binary inspirals is simulated and the results of simulation used as the templates. This gives good sensitivity for events which match the models, as well as identifying a best fit template which gives an indication of the cause of the event (i.e. mass, spin, distance of the merger event)

Recognising that this type of analysis would fail to detect unexpected events, a second search process operates using a different method - in this case, by detecting coherent wave bursts - In other words, the near-simultaneous detection of the same arbitrary waveforms by 2 or 3 detectors, which meet some sort of threshold (likely based on measured or observed noise levels/characteristics in the detectors and a statistical model giving an estimate of the false positive rate).-+

Up till now, all the GW events have been detected by the template matching pipeline. This event was detected only by the coherent wave burst pipeline without triggering the template matching pipeline. Interestingly, the direction estimates from the phase/polarization differences in the detection at the different sites are extremely narrow, which may indicate a very high SNR measurement at all 3 detectors (i.e. a particularly strong event).

Note that the search process intended for formal scientific publication uses a much more complex set of off-line analysis and optimisation pipelines. The low latency alerts are intended for other astronomers who wish to collaborate on multi-messenger observations (e.g. gamma ray, visible light) who require a target ASAP. If you look through the various archives, you will see a lot of the preliminary low-latency alerts are retracted some time later after further analysis suggests a glitch or terrestrial event.

Re:

[Alwin Barni]

Thanks, so hence "unanticipated", as it didn't match any known models of such events?
Do you know anything more about this signal, as it was detected by all 3 detectors it might be an actual event, so is there any theoretical model, which would match the recorded signal?

Re:

[ChumpusRex2003]

The only information publicly available is the graceDB page for the event (called S200114f). The LIGO/VIRGO policy is to publish only limited information as early alerts (e.g. which pipeline found the event, what class of template was matched, where in the sky was the source), which is of key interest to other astronomers. The remaining data is kept confidential pending internal review, and formal peer review prior before publication.

However, one parameter that is published is the duration of the signal

Re:

[RockDoctor]

This parameter is opaque, as the template matching pipeline works on 1 second templates,

Hmmm, I had noted that an event report had been giving two 1 second duration measures (measured to the microsecond), and I wondered what was up with that. I didn't believe for one second that the 1-in-1000000 accuracy of the match of the two durations given had any physical significance.

Re:

[Alwin Barni]

Thank you for all the details, it's really interesting (the gravitational waves detection) - especially with regard to recently suggested possible prove for Hawking BH description, which might result in detectable echos.

I have a less scientific question though: considering the Alcubierre drive (I know all the drawbacks - it's just a theoretical question) - would such a drive generate any detectable signal from some reasonable distance, let's say few parsecs?

Also a more scientific one: would it be possible