Did LIGO detect gravitational waves from rotating neutron stars?

Otubak
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Topic 214444

https://retriever.umbc.edu/thomas-carruthers-speaks-about-ligo-and-gravitational-waves/

“Pulsars are rapidly rotating stars. LIGO had observed mountains on pulsars,"

 

This pretty much sounds like they found something, and I wonder what this means for E@H if they actually did (or whether E@H was involved).

I have no idea how reliable this source is, but I didn't see anything obviously wrong with it.

Jim1348
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It could be that it is

It could be that it is unpublished, and embargoed for a while.

astro-marwil
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Hallo! In the past,  these

Hallo!

In the past,  these calculations were carried out on the ATLAS-computer. This application is too small to become crunched effectively on E@H. 

But in this article is a doubviously citate also :

Sandhaus described the experience as informative and enlightening. “The coolest thing about gravitational waves is that we could theoretically learn about things that happen inside the event horizon [of a black hole],” she said.

As far as I know, this is impossible, as GW are travelling with speed of light. So they can´t escape from inside the event horizon by definition of this. 

Kind regards and happy crunching

Martin

Mike Hewson
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astro-marwil wrote:“The

astro-marwil wrote:
“The coolest thing about gravitational waves is that we could theoretically learn about things that happen inside the event horizon [of a black hole],” she said.Martin

Maybe referring to alternate extensions of GR ie. theory yet to be validated. Plain vanilla GR precludes peeking inside the horizon from a distance. An ingoing horizon crossing observer will learn plenty no doubt, but not be able ( despite Hollywood ) to pass that on to us! One would like to know the context of the comment. 

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

astro-marwil
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Hallo! There is a new strong

Hallo!

There is a new strong working group at MPI-AEI for the search for continuous GW. They will use E@H for their work.

Best wishes for success!

Kind regards and happy crunching

Martin

astro-marwil
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Hallo! There are even more

Hallo!

There are even more potential sources of continuous GW from Neutron Stars with week magnetic field, that can not be seen by radio astronomy.

Kind regards and happy crunching

Martin

Jim1348
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astro-marwil wrote:There are

astro-marwil wrote:
There are even more potential sources of continuous GW from Neutron Stars with week magnetic field, that can not be seen by radio astronomy.

That is quite interesting, but I don't know how you would associate any continuous GW source that we would see with any particular object found by other means.  I don't think there is any directional information (or distance) in our work, unless they can think of some clever way of adding it.

Gary Roberts
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Jim1348 wrote:... I don't

Jim1348 wrote:
... I don't know how you would associate any continuous GW source ...

If the signal was available from multiple detectors, wouldn't you be able to perform a 'fuzzy' form of triangulation - like what was done to identify the location of the source for the recent NS-NS merger?  But we're jumping the gun a bit here - until there is an actual detection ... and probably a lot more sensitivity improvement ... might not happen for a while yet :-).

 

Cheers,
Gary.

Gary Roberts
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astro-marwil wrote:There is a

astro-marwil wrote:
There is a new strong working group at MPI-AEI for the search for continuous GW.

Thanks for the link.  I liked the group photo - brought back memories of the 'Open Day' at the AEI back in 2011.  I recognise some of the faces.  You can't miss Bernd.  Just look for 'Big Bird' just to the right of Dr Papa with Oliver a couple to the right and 'HB' (Heinz-Bernd - who doesn't post much these days) three to the left and looking like he's about to launch himself over the rail :-)

I liked the unintended irony of the caption, "The Research Group Searching for Continuous Gravitational Waves in the Summer of 2017" with everybody gazing into the distance.  They're all looking in completely the wrong direction!!  They should be looking DOWN!!  ... under the bridge fellas ... look at all those lovely little 'waves' down there!!! SurprisedWinkLaughing

 

Cheers,
Gary.

Jim1348
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Gary Roberts wrote:If the

Gary Roberts wrote:
If the signal was available from multiple detectors, wouldn't you be able to perform a 'fuzzy' form of triagulation - like what was done to identify the location of the source for the recent NS-NS merger? 

It appears to me that when you have to operate on many sets of data from all the detectors to dig the signal out of the noise, you lose the position information.  Maybe if they operate on the data from each detector separately, they can still retain some of that, so I am speculating a bit on how they operate.  You are right, we will have to wait and see.

Gary Roberts
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On thinking a bit more about

On thinking a bit more about this (without knowing anything of the physics behind it) I seem to recall that one crucial piece of information was the time delay between different detectors 'seeing' the signal. That's all well and good for an event with a well defined starting point (or well defined, rapidly decaying event wave-form) like a BH-BH merger.  I guess it would be different for continuous GW - no start or end.  Maybe it would be some sort of phase difference.

If that were so, I'm sure the effort would be made to separate the data from each observatory to allow that type of measurement to be made. It must be one of the reasons behind building multiple (and expensive) LIGO instruments.

 

Cheers,
Gary.

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