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Created talk-page for the GW170817 article - Enjoy! :) Drbogdan ( talk) 00:52, 28 August 2017 (UTC)
This is more speculation than anything else. I don't think this is an article Wikipedia should have at the moment. Pages should be about things with lasting significance. What do you write if the analysis shows there was no event? If an article can lose its significance, then it never had enough significance. -- mfb ( talk) 12:59, 28 August 2017 (UTC)
Thanks for all the comments - my present thinking at the moment => seems a wait-and-see approach may be the better road - may not be long I would think - if " GW170818" is confirmed and an official name noted, then the article name (and article contents) can easily be adjusted if necessary - if the GW event is not confirmed, then the article can easily be removed (or at least modified to some extent) if necessary - either way is *entirely* ok with me atm - Thanks again for the comments - and - Enjoy! :) Drbogdan ( talk) 01:54, 29 August 2017 (UTC)
References
QUESTION: Could a " Gamma-Ray Burst (GRB)" of an astrophysical event be detected before the " Gravitational Wave (GW)" of the very same event? - or not? - if so, then " GRB 170817A" could be detected some (brief?) time before " GW170817" for the very same astrophysical event - Comments Welcome if possible - in any regards - Enjoy! :) Drbogdan ( talk) 02:55, 29 August 2017 (UTC)
FWIW - seems related => "... a gamma-ray signal arrived nearly at the same exact time as the gravitational waves, with less than a 2-second difference in arrival time. Across a journey of more than 100 million light-years, that one measurement both confirmed that gravitational waves and electromagnetic waves travel at the same speed to within 15 significant digits ..." [3] - in any case - Enjoy! :) Drbogdan ( talk) 16:41, 30 July 2019 (UTC)
UPDATE: Seems a gravitational wave may arrive before a light wave in some related instances, according to a recent science report. [5] - Drbogdan ( talk) 12:55, 26 October 2023 (UTC)
References
nature.com gave it a short article, summarizing all the major telescope priority interrupts that suddenly found a certain obscure galaxy interesting, one of them naming this GW by number in its public database. Those interruptions are certainly not a rumor, and such a confluence has made it to the science press.
We are not a crystal ball, but there are only a small number of ways this much "exciting" data collection will play out. Either one or both of the GW/GRB will be confirmed, or both will be disconfirmed. So perhaps this article will be renamed GW170818 anomaly or LVT170818 in the end, reporting on what the RS say about the fluke and what it means for LIGO. Either way, it seems clear there will be an article on this topic.
Compare 750 GeV diphoton excess. 129.68.81.144 ( talk) 15:31, 29 August 2017 (UTC)
I rewrote the body of the article. I also edited Wikidata. Note that we cannot call this the "fourth" signal, nor identify what the "previous" signal was. LSC/Virgo has said they are analyzing seven [possible correction by (
Drbogdan (
talk) 11:52, 30 August 2017 (UTC)): better "several" instead? - please see => “promising gravitational-wave candidates”
[1]
[2] earlier triggers, and I expect their next signal announcement will be for something seen in February or March. The one detail missing is that this might have been seen under triple lock.
I don't think it's worth naming anyone except the fellow who started the rumor game.
I think maybe we can leave out the under construction template, it's just normal editing now. Drbogdan? 129.68.81.144 ( talk) 16:29, 29 August 2017 (UTC)
References
I had entered the claim that the name GW170818 was seen in a trigger statement, which I had recalled reading earlier in the week, I thought in Nature or Quanta or New Scientist. I was unable to find it, so I deleted the claim.
Now I have to ask: Drbogdan, where did you get the name? Did you mistake the date of Wheeler's tweet for the discovery date? If so, it seems you should just rename the article to one day earlier. The most information seems to be the discussion at [1]. 129.68.81.144 ( talk) 20:32, 29 August 2017 (UTC)
"{{cn|date=August 2017}}"
- for my part at the moment => until an official name has been posted in a "
WP:RS", the present article name (ie, "
GW170818") may be as good as any other - however - if someone thinks otherwise - renaming the article (esp if there's some ok rationale to do so), is *entirely* ok with me - hope this helps in some way - iac - Enjoy! :)
Drbogdan (
talk) 21:18, 29 August 2017 (UTC)
Yes, there are seven triggers in the source. Move down the page to 7/7/17 news. They mention 8 triggers, and then state that one of them has been confirmed.
All year LSC had been announcing updates on exact trigger counts. (Scroll down, you'll see the numbers grew over time.) My guess is they decided to go vague in response to the rumors, refusing to give an exact count, which if more than 8, would provide more fuel for speculation. 129.68.81.173 ( talk) 15:43, 31 August 2017 (UTC)
Before we repeat the same detailed information in lots of places, I think we need a page that deals with the detected collision event as a whole. That is, one that is separate from the specific components, e.g. the gravity wave GW170817 and the GRB 170817A, the many observatories involved, its location NGC 4993 and also separate from the type of event neutron star collision. Does the detected event itself have an official name?
The new page would cover all the aspects mentioned in the 2-hour press release that is on Youtube, whereas the above linked pages do not need to contain all that information. (Not suggesting that they do, but there is that temptation).
Thoughts? Tayste ( edits) 21:34, 16 October 2017 (UTC)
References
I thought I read somewhere (in the Wiki-guidelines?) that all articles are supposed to be aimed at "an intelligent college student". This article, as is sits right now, is more of a graduate textbook section in multi-messenger astronomy. If you don't supply context in the article itself, the vast number of readers (intelligent college students) will be turned off and won't follow the wiki-links.
I'm not saying that any of the material you have already should be eliminated. I am saying that what you have should be explained down to an undergraduate level. For example, the phrase in the lead paragraph "the first gravitational wave detection of the merger of two neutron stars, and was associated with a soft short gamma-ray burst GRB 170817A, and an optical transient that was found in the galaxy NGC 4993" should explain (a) what a "gamma-ray burst" and an "optical transient" are and (b) which of the two events (merger of two neutron stars or the association of a gamma-ray burst and an optical transient) was the first. I'm right, aren't I, that whatever is first makes the event worthy of inclusion as a separate article?
I could start to make the additions myself but, as you can see, I don't really have the depth of knowledge to judge the precedence of what I'm adding. And when you get into "scalar–tensor theory and Hořava–Lifshitz gravity", I am totally lost. -- RoyGoldsmith ( talk) 05:33, 18 October 2017 (UTC)
@ Earthandmoon: I'm not sure I like this second-try edit, but it's not wrong so I'll discuss it here rather than reverting for a second time.
The details are already there, in GW170817 § Electromagnetic observations. Your edit consists of copying them into the lead, and I think it's cluttering more than helping. Could you explain why you think that helps? 104.153.72.218 ( talk)
I'm familiar with basic physics, but I'm missing information to understand the topic at first reading. I understand first indication was the gravity wave detection (by LIGO/Virgo), and then ~all available telescopes were directed to measure other radiation from that point. That came 11 hrs later, enough time to redirect a telescope OK. But hey, when everything is happening at speed of light, how these 11 hrs of extra time? IMO, this could be explained in article body, and should be mentioned in the lede. - DePiep ( talk) 20:20, 19 October 2017 (UTC)
As long as we're on the subject, what event do we think we observed? (Let's say of the gravitational wave signal since it appears first.) Let's say it was the merging of two neutron starts to create a black hole. What was the first event we could observe? Was it the forming of the event horizon surrounding the first particle (quanta) of the neutron stars? Or something before the event horizon, when the stars are dancing around each other at a speed approaching that of light? What about the relativity effects? The GWS lasted about 100 seconds. Could that be the total time it took to transform the two stars into one singularity? What if the merging only created a more massive neutron star? -- RoyGoldsmith ( talk)
@ RoyGoldsmith: I undid your edit for several reasons, actually, and I'd like to figure out what you're trying to do in order to better achieve it. The boilerplace in undos doesn't leave a lot of room for a good edit comment, so let me expand here:
Although I used point 1 as justification for the undo, it's actually point 3 that got my attention first; I quite dislike that phrasing. I'm having a hard time inferring what the problem is that you were trying to fix. Could we discuss it to find a fix that we both like? 104.153.72.218 ( talk) 08:31, 20 October 2017 (UTC)
@ Eric Kvaalen: Likewise. This is not repeat not the first observation of merging neutron stars; it's just by far the best observation. Perhaps I need to put words in the article to that effect?
Any ideas how to boil all that down to a short message that can fit into the article? Any any ideas where to put it? 104.153.72.218 ( talk) 12:15, 20 October 2017 (UTC)
P.S. I added a paragraph to § Scientific importance since this appears to be a common misunderstanding. Feel free to revise/improve/move, of course. 104.153.72.218 ( talk) 12:40, 20 October 2017 (UTC)
@ Mike Peel: 'so' implies causality that isn't definite. Er, what? The causality absolutely is definite. Black holes cannot be seen, full stop. They can be detected optically only by to their gravitational effects on other visible, matter: gravitational lensing, perturbation of the orbits of visible matter, or heating of infalling matter. However, a closely spaced binary pair has long since eaten or ejected all nearby normal matter, so there's nothing else to glow, either. If an optical counterpart were seen, that would be very unexpected indeed.
To quote this LIGO press release:
LIGO and VIRGO’s partner electromagnetic facilities around the world didn’t identify a counterpart for GW170814, which was similar to the three prior LIGO observations of black hole mergers. Black holes produce gravitational waves but not light.
Can you explain why you think it's not definite? Astronomers looked, just in case, but didn't expect to find anything. Anything that would produce such an effect is a WP:FRINGE theory that doesn't deserve undue weight. 104.153.72.218 ( talk) 14:31, 20 October 2017 (UTC)
{{
cite news}}
: Cite has empty unknown parameter: |1=
(
help)Despite the lack of an NS component and the large distance, we triggered our follow-up program given the relatively small localization region.
{{
cite journal}}
: CS1 maint: unflagged free DOI (
link)</ref>... of merging black holes and were generally not expected to have detectable electromagnetic counterparts. Gap9551 ( talk) 16:31, 20 October 2017 (UTC)
{{
efn}}
explanatory footnote, which you should both feel free to edit fiercely; I'm not sure I like it myself.
104.153.72.218 (
talk) 17:01, 20 October 2017 (UTC)
Perhaps the image in the gallery could be integrated into the prose somehow? For one, I don't think galleries are encouraged, and two, it looks super awkward with just one image. --- Another Believer ( Talk) 02:15, 22 October 2017 (UTC)
@ Rkinch, Mike Peel, and Gap9551: I'm sorry that an edit message doesn't leave a lot of room for an explanation. I try, but especially if half of the space is taken up with an undo message, what remains has to be quite terse. In full detail, the reason that the GW source location computation should not be described as triangulation:
Triangulation is used by astronomers; it's the basis of the method of parallax. A star whose parallax is one arc second when measured at opposite ends of the Earth's orbit has a distance of one parsec. One tenth of an arc second is ten parsecs, etc. This is limited to nearby stars; as distances get farther, the angles get smaller and harder to measure. The most accurate astrometric angle measuring instrument today is Gaia (spacecraft), which is capable of measuring angles to 20 microarcseconds, or 50,000 parsec. Even if the baseline were 1 au (as we don't have six months to wait, it's not; it's the much smaller distance between GW detectors) 40,000,000 parsec would produce a parallax angle indistinguishable from zero.
The GW detectors are receiving a plane wave, and even with three receivers only the direction of the source can be computed. (The distance is computed by different means; see Cosmic distance ladder § Standard siren.)
I don't know why LIGO published that figure caption. I presume it's someone tasked with public relations who is being sloppy with language. That doesn't mean that Wikipedia should copy it. 104.153.72.218 ( talk) 12:33, 25 October 2017 (UTC)
@ 31.18.248.183: Re: this deletion of "and spurred frantic excitement and further analysis." A few days ago, I had a non-technical friend read the article (which led to several edits on my part), and the word "frantic" was specifically called out to me as a good thing which added flavour to an otherwise dry article. AFAICT, it's an accurate description. Your deletion had no edit comment. Can you elaborate on why that needed to die? 104.153.72.218 ( talk) 09:44, 27 October 2017 (UTC)
@ TychosElk: Re: this correction. Thank you; my bad. The press conference included a speaker from the Las Campanas Observatory describing the follow-up search, so I assumed that was the acronym. The source, of course, says Las Cumbres Observatory. Thank you for fixing it. 104.153.72.218 ( talk) 10:20, 27 October 2017 (UTC)
My changes were undone. I fixed a major misunderstanding in the AT2017gfo section, added (some) relevant references and removed references that were either not relevant or misplaced. Why? [added => 18:52, 29 October 2017 Aldebarahan ( talk | contribs)]
|volume=826
and |issue=1
parameters were incorrect. And why'd you delete the de Mink reference? That references was needed to support the claim in the explanatory footnote.@ CA2MI: Re: "GW170817 is a transient multi-messenger event observed on 17 August 2017 by the LIGO and Virgo detectors, which recorded a gravitational wave (GW) signal produced by two neutron stars"
There's a grammar problem here. If you're talking about the source, or even the observation, that was; its over and done with. The recorded signal (which is what the previous/reverted text refers to) still exists, so it is.
Also, the article goes to some trouble to distinguish the GW/GRB/AT signals, and this change to the definition of what GW170817 is (from GW signal to astronomical source) a bit too much confusion. When we're conflating things, we use the more generic "event". (I don't have a problem with this conflation in most contexts, as that's how astronomers speak normally. It's akin to how the "event" of a coronation is the ceremony proper and the invited guests and the parade and the parade spectators and the protestors and so on.)
But more than that, "multi-messenger" describes the observation more than the source. Not only are all astronomical sources technically multi-messenger, even potentially detectable ones are apparently not all that rare. What's new is that this is the first time everything has been in place to actually observe one.
The end of the first paragraph and entirety of the second is already all about the multi-messenger aspect. Do we really need to move it up more? 104.153.72.218 ( talk) 15:47, 4 November 2017 (UTC)
@ CA2MI: Re: "GW170817 was a multi-messenger observation of a transient astronomical event" No, it wasn't that, either. It was a single-messenger observation. GRB 170817A was also a single-messenger observation. The combination of the two was a multi-messenger observation. Does the article not make that clear enough?
I'm assuming you missed what I wrote above about multi-messenger already being quite prominent, so please read that now. 104.153.72.218 ( talk) 21:16, 4 November 2017 (UTC)
To continue, while astronomers speaking casually use the names GW170817, GRB 170817A and AT 2017gfo interchangeably to refer to the same astronomical event, more formally they're distinct observations. That's the entire point of the bullet list in the lead. The qualitatively different observations is what makes this multi-messenger astronomy. (The fact that multi-messenger astronomy is very new is why there aren't well-established conventions for resolving the name conflict.) If you think the article should be rewritten to eliminate the distinction, do it (or preferably discuss such a major change here first), but please don't half do it, resulting in an article that contradicts itself.
Just as a minor point, MOS:DUPLINK prefers to wikilink the first occurrence of a phrase in an article, and not subsequent ones. If you add a wikilink to multi-messenger astronomy to the beginning of the lead paragraph, please unlink those words from the end of it. (Or you could leave "multi-messenger" unlinked in preference to an unpiped link of the exact words slightly later.) 104.153.72.218 ( talk) 21:35, 4 November 2017 (UTC)
@ Drbogdan: Regarding your latest edits:
Is that telegram really speaking about observing separate X-ray emissions from GW170817, GRB170817A and SSS17a? It seems to me that it's just naming the already known connected events, while settling on mostly using the name GRB170817A (which I otherwise thought referred to the 2 second GRB) for the new X-ray observations. -- Ørjan ( talk) 23:11, 9 December 2017 (UTC)
References
Apparently GW170817 is putting out a superluminal jet. (This is a well-known relativistic optical illusion; it's not really travelling faster than light.) I don't have time to edit the article, so I'm dumping some references here in case someone else wants to pick up the editorial pen.
209.209.238.149 ( talk) 20:56, 24 November 2018 (UTC)
FWIW - worthy recent reference [1] (in some way?) for this (or related) article? - seems clear - and well written - Comments Welcome - in any case - Enjoy! :) Drbogdan ( talk) 14:58, 30 July 2019 (UTC)
References
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Created talk-page for the GW170817 article - Enjoy! :) Drbogdan ( talk) 00:52, 28 August 2017 (UTC)
This is more speculation than anything else. I don't think this is an article Wikipedia should have at the moment. Pages should be about things with lasting significance. What do you write if the analysis shows there was no event? If an article can lose its significance, then it never had enough significance. -- mfb ( talk) 12:59, 28 August 2017 (UTC)
Thanks for all the comments - my present thinking at the moment => seems a wait-and-see approach may be the better road - may not be long I would think - if " GW170818" is confirmed and an official name noted, then the article name (and article contents) can easily be adjusted if necessary - if the GW event is not confirmed, then the article can easily be removed (or at least modified to some extent) if necessary - either way is *entirely* ok with me atm - Thanks again for the comments - and - Enjoy! :) Drbogdan ( talk) 01:54, 29 August 2017 (UTC)
References
QUESTION: Could a " Gamma-Ray Burst (GRB)" of an astrophysical event be detected before the " Gravitational Wave (GW)" of the very same event? - or not? - if so, then " GRB 170817A" could be detected some (brief?) time before " GW170817" for the very same astrophysical event - Comments Welcome if possible - in any regards - Enjoy! :) Drbogdan ( talk) 02:55, 29 August 2017 (UTC)
FWIW - seems related => "... a gamma-ray signal arrived nearly at the same exact time as the gravitational waves, with less than a 2-second difference in arrival time. Across a journey of more than 100 million light-years, that one measurement both confirmed that gravitational waves and electromagnetic waves travel at the same speed to within 15 significant digits ..." [3] - in any case - Enjoy! :) Drbogdan ( talk) 16:41, 30 July 2019 (UTC)
UPDATE: Seems a gravitational wave may arrive before a light wave in some related instances, according to a recent science report. [5] - Drbogdan ( talk) 12:55, 26 October 2023 (UTC)
References
nature.com gave it a short article, summarizing all the major telescope priority interrupts that suddenly found a certain obscure galaxy interesting, one of them naming this GW by number in its public database. Those interruptions are certainly not a rumor, and such a confluence has made it to the science press.
We are not a crystal ball, but there are only a small number of ways this much "exciting" data collection will play out. Either one or both of the GW/GRB will be confirmed, or both will be disconfirmed. So perhaps this article will be renamed GW170818 anomaly or LVT170818 in the end, reporting on what the RS say about the fluke and what it means for LIGO. Either way, it seems clear there will be an article on this topic.
Compare 750 GeV diphoton excess. 129.68.81.144 ( talk) 15:31, 29 August 2017 (UTC)
I rewrote the body of the article. I also edited Wikidata. Note that we cannot call this the "fourth" signal, nor identify what the "previous" signal was. LSC/Virgo has said they are analyzing seven [possible correction by (
Drbogdan (
talk) 11:52, 30 August 2017 (UTC)): better "several" instead? - please see => “promising gravitational-wave candidates”
[1]
[2] earlier triggers, and I expect their next signal announcement will be for something seen in February or March. The one detail missing is that this might have been seen under triple lock.
I don't think it's worth naming anyone except the fellow who started the rumor game.
I think maybe we can leave out the under construction template, it's just normal editing now. Drbogdan? 129.68.81.144 ( talk) 16:29, 29 August 2017 (UTC)
References
I had entered the claim that the name GW170818 was seen in a trigger statement, which I had recalled reading earlier in the week, I thought in Nature or Quanta or New Scientist. I was unable to find it, so I deleted the claim.
Now I have to ask: Drbogdan, where did you get the name? Did you mistake the date of Wheeler's tweet for the discovery date? If so, it seems you should just rename the article to one day earlier. The most information seems to be the discussion at [1]. 129.68.81.144 ( talk) 20:32, 29 August 2017 (UTC)
"{{cn|date=August 2017}}"
- for my part at the moment => until an official name has been posted in a "
WP:RS", the present article name (ie, "
GW170818") may be as good as any other - however - if someone thinks otherwise - renaming the article (esp if there's some ok rationale to do so), is *entirely* ok with me - hope this helps in some way - iac - Enjoy! :)
Drbogdan (
talk) 21:18, 29 August 2017 (UTC)
Yes, there are seven triggers in the source. Move down the page to 7/7/17 news. They mention 8 triggers, and then state that one of them has been confirmed.
All year LSC had been announcing updates on exact trigger counts. (Scroll down, you'll see the numbers grew over time.) My guess is they decided to go vague in response to the rumors, refusing to give an exact count, which if more than 8, would provide more fuel for speculation. 129.68.81.173 ( talk) 15:43, 31 August 2017 (UTC)
Before we repeat the same detailed information in lots of places, I think we need a page that deals with the detected collision event as a whole. That is, one that is separate from the specific components, e.g. the gravity wave GW170817 and the GRB 170817A, the many observatories involved, its location NGC 4993 and also separate from the type of event neutron star collision. Does the detected event itself have an official name?
The new page would cover all the aspects mentioned in the 2-hour press release that is on Youtube, whereas the above linked pages do not need to contain all that information. (Not suggesting that they do, but there is that temptation).
Thoughts? Tayste ( edits) 21:34, 16 October 2017 (UTC)
References
I thought I read somewhere (in the Wiki-guidelines?) that all articles are supposed to be aimed at "an intelligent college student". This article, as is sits right now, is more of a graduate textbook section in multi-messenger astronomy. If you don't supply context in the article itself, the vast number of readers (intelligent college students) will be turned off and won't follow the wiki-links.
I'm not saying that any of the material you have already should be eliminated. I am saying that what you have should be explained down to an undergraduate level. For example, the phrase in the lead paragraph "the first gravitational wave detection of the merger of two neutron stars, and was associated with a soft short gamma-ray burst GRB 170817A, and an optical transient that was found in the galaxy NGC 4993" should explain (a) what a "gamma-ray burst" and an "optical transient" are and (b) which of the two events (merger of two neutron stars or the association of a gamma-ray burst and an optical transient) was the first. I'm right, aren't I, that whatever is first makes the event worthy of inclusion as a separate article?
I could start to make the additions myself but, as you can see, I don't really have the depth of knowledge to judge the precedence of what I'm adding. And when you get into "scalar–tensor theory and Hořava–Lifshitz gravity", I am totally lost. -- RoyGoldsmith ( talk) 05:33, 18 October 2017 (UTC)
@ Earthandmoon: I'm not sure I like this second-try edit, but it's not wrong so I'll discuss it here rather than reverting for a second time.
The details are already there, in GW170817 § Electromagnetic observations. Your edit consists of copying them into the lead, and I think it's cluttering more than helping. Could you explain why you think that helps? 104.153.72.218 ( talk)
I'm familiar with basic physics, but I'm missing information to understand the topic at first reading. I understand first indication was the gravity wave detection (by LIGO/Virgo), and then ~all available telescopes were directed to measure other radiation from that point. That came 11 hrs later, enough time to redirect a telescope OK. But hey, when everything is happening at speed of light, how these 11 hrs of extra time? IMO, this could be explained in article body, and should be mentioned in the lede. - DePiep ( talk) 20:20, 19 October 2017 (UTC)
As long as we're on the subject, what event do we think we observed? (Let's say of the gravitational wave signal since it appears first.) Let's say it was the merging of two neutron starts to create a black hole. What was the first event we could observe? Was it the forming of the event horizon surrounding the first particle (quanta) of the neutron stars? Or something before the event horizon, when the stars are dancing around each other at a speed approaching that of light? What about the relativity effects? The GWS lasted about 100 seconds. Could that be the total time it took to transform the two stars into one singularity? What if the merging only created a more massive neutron star? -- RoyGoldsmith ( talk)
@ RoyGoldsmith: I undid your edit for several reasons, actually, and I'd like to figure out what you're trying to do in order to better achieve it. The boilerplace in undos doesn't leave a lot of room for a good edit comment, so let me expand here:
Although I used point 1 as justification for the undo, it's actually point 3 that got my attention first; I quite dislike that phrasing. I'm having a hard time inferring what the problem is that you were trying to fix. Could we discuss it to find a fix that we both like? 104.153.72.218 ( talk) 08:31, 20 October 2017 (UTC)
@ Eric Kvaalen: Likewise. This is not repeat not the first observation of merging neutron stars; it's just by far the best observation. Perhaps I need to put words in the article to that effect?
Any ideas how to boil all that down to a short message that can fit into the article? Any any ideas where to put it? 104.153.72.218 ( talk) 12:15, 20 October 2017 (UTC)
P.S. I added a paragraph to § Scientific importance since this appears to be a common misunderstanding. Feel free to revise/improve/move, of course. 104.153.72.218 ( talk) 12:40, 20 October 2017 (UTC)
@ Mike Peel: 'so' implies causality that isn't definite. Er, what? The causality absolutely is definite. Black holes cannot be seen, full stop. They can be detected optically only by to their gravitational effects on other visible, matter: gravitational lensing, perturbation of the orbits of visible matter, or heating of infalling matter. However, a closely spaced binary pair has long since eaten or ejected all nearby normal matter, so there's nothing else to glow, either. If an optical counterpart were seen, that would be very unexpected indeed.
To quote this LIGO press release:
LIGO and VIRGO’s partner electromagnetic facilities around the world didn’t identify a counterpart for GW170814, which was similar to the three prior LIGO observations of black hole mergers. Black holes produce gravitational waves but not light.
Can you explain why you think it's not definite? Astronomers looked, just in case, but didn't expect to find anything. Anything that would produce such an effect is a WP:FRINGE theory that doesn't deserve undue weight. 104.153.72.218 ( talk) 14:31, 20 October 2017 (UTC)
{{
cite news}}
: Cite has empty unknown parameter: |1=
(
help)Despite the lack of an NS component and the large distance, we triggered our follow-up program given the relatively small localization region.
{{
cite journal}}
: CS1 maint: unflagged free DOI (
link)</ref>... of merging black holes and were generally not expected to have detectable electromagnetic counterparts. Gap9551 ( talk) 16:31, 20 October 2017 (UTC)
{{
efn}}
explanatory footnote, which you should both feel free to edit fiercely; I'm not sure I like it myself.
104.153.72.218 (
talk) 17:01, 20 October 2017 (UTC)
Perhaps the image in the gallery could be integrated into the prose somehow? For one, I don't think galleries are encouraged, and two, it looks super awkward with just one image. --- Another Believer ( Talk) 02:15, 22 October 2017 (UTC)
@ Rkinch, Mike Peel, and Gap9551: I'm sorry that an edit message doesn't leave a lot of room for an explanation. I try, but especially if half of the space is taken up with an undo message, what remains has to be quite terse. In full detail, the reason that the GW source location computation should not be described as triangulation:
Triangulation is used by astronomers; it's the basis of the method of parallax. A star whose parallax is one arc second when measured at opposite ends of the Earth's orbit has a distance of one parsec. One tenth of an arc second is ten parsecs, etc. This is limited to nearby stars; as distances get farther, the angles get smaller and harder to measure. The most accurate astrometric angle measuring instrument today is Gaia (spacecraft), which is capable of measuring angles to 20 microarcseconds, or 50,000 parsec. Even if the baseline were 1 au (as we don't have six months to wait, it's not; it's the much smaller distance between GW detectors) 40,000,000 parsec would produce a parallax angle indistinguishable from zero.
The GW detectors are receiving a plane wave, and even with three receivers only the direction of the source can be computed. (The distance is computed by different means; see Cosmic distance ladder § Standard siren.)
I don't know why LIGO published that figure caption. I presume it's someone tasked with public relations who is being sloppy with language. That doesn't mean that Wikipedia should copy it. 104.153.72.218 ( talk) 12:33, 25 October 2017 (UTC)
@ 31.18.248.183: Re: this deletion of "and spurred frantic excitement and further analysis." A few days ago, I had a non-technical friend read the article (which led to several edits on my part), and the word "frantic" was specifically called out to me as a good thing which added flavour to an otherwise dry article. AFAICT, it's an accurate description. Your deletion had no edit comment. Can you elaborate on why that needed to die? 104.153.72.218 ( talk) 09:44, 27 October 2017 (UTC)
@ TychosElk: Re: this correction. Thank you; my bad. The press conference included a speaker from the Las Campanas Observatory describing the follow-up search, so I assumed that was the acronym. The source, of course, says Las Cumbres Observatory. Thank you for fixing it. 104.153.72.218 ( talk) 10:20, 27 October 2017 (UTC)
My changes were undone. I fixed a major misunderstanding in the AT2017gfo section, added (some) relevant references and removed references that were either not relevant or misplaced. Why? [added => 18:52, 29 October 2017 Aldebarahan ( talk | contribs)]
|volume=826
and |issue=1
parameters were incorrect. And why'd you delete the de Mink reference? That references was needed to support the claim in the explanatory footnote.@ CA2MI: Re: "GW170817 is a transient multi-messenger event observed on 17 August 2017 by the LIGO and Virgo detectors, which recorded a gravitational wave (GW) signal produced by two neutron stars"
There's a grammar problem here. If you're talking about the source, or even the observation, that was; its over and done with. The recorded signal (which is what the previous/reverted text refers to) still exists, so it is.
Also, the article goes to some trouble to distinguish the GW/GRB/AT signals, and this change to the definition of what GW170817 is (from GW signal to astronomical source) a bit too much confusion. When we're conflating things, we use the more generic "event". (I don't have a problem with this conflation in most contexts, as that's how astronomers speak normally. It's akin to how the "event" of a coronation is the ceremony proper and the invited guests and the parade and the parade spectators and the protestors and so on.)
But more than that, "multi-messenger" describes the observation more than the source. Not only are all astronomical sources technically multi-messenger, even potentially detectable ones are apparently not all that rare. What's new is that this is the first time everything has been in place to actually observe one.
The end of the first paragraph and entirety of the second is already all about the multi-messenger aspect. Do we really need to move it up more? 104.153.72.218 ( talk) 15:47, 4 November 2017 (UTC)
@ CA2MI: Re: "GW170817 was a multi-messenger observation of a transient astronomical event" No, it wasn't that, either. It was a single-messenger observation. GRB 170817A was also a single-messenger observation. The combination of the two was a multi-messenger observation. Does the article not make that clear enough?
I'm assuming you missed what I wrote above about multi-messenger already being quite prominent, so please read that now. 104.153.72.218 ( talk) 21:16, 4 November 2017 (UTC)
To continue, while astronomers speaking casually use the names GW170817, GRB 170817A and AT 2017gfo interchangeably to refer to the same astronomical event, more formally they're distinct observations. That's the entire point of the bullet list in the lead. The qualitatively different observations is what makes this multi-messenger astronomy. (The fact that multi-messenger astronomy is very new is why there aren't well-established conventions for resolving the name conflict.) If you think the article should be rewritten to eliminate the distinction, do it (or preferably discuss such a major change here first), but please don't half do it, resulting in an article that contradicts itself.
Just as a minor point, MOS:DUPLINK prefers to wikilink the first occurrence of a phrase in an article, and not subsequent ones. If you add a wikilink to multi-messenger astronomy to the beginning of the lead paragraph, please unlink those words from the end of it. (Or you could leave "multi-messenger" unlinked in preference to an unpiped link of the exact words slightly later.) 104.153.72.218 ( talk) 21:35, 4 November 2017 (UTC)
@ Drbogdan: Regarding your latest edits:
Is that telegram really speaking about observing separate X-ray emissions from GW170817, GRB170817A and SSS17a? It seems to me that it's just naming the already known connected events, while settling on mostly using the name GRB170817A (which I otherwise thought referred to the 2 second GRB) for the new X-ray observations. -- Ørjan ( talk) 23:11, 9 December 2017 (UTC)
References
Apparently GW170817 is putting out a superluminal jet. (This is a well-known relativistic optical illusion; it's not really travelling faster than light.) I don't have time to edit the article, so I'm dumping some references here in case someone else wants to pick up the editorial pen.
209.209.238.149 ( talk) 20:56, 24 November 2018 (UTC)
FWIW - worthy recent reference [1] (in some way?) for this (or related) article? - seems clear - and well written - Comments Welcome - in any case - Enjoy! :) Drbogdan ( talk) 14:58, 30 July 2019 (UTC)
References