Gravity Waves

[Aardwolf]

Since I didn't design their equipment, I'm not entirely clear how often we should expect to unambiguously observe "gravity wave signals" over the course of a year...

When they begged for the $200m upgrade it was expected to detect on average about 40 events per year with potential for up to 400 per year.

http://arxiv.org/abs/1003.2480

We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the Initial and Advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters, and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our Galaxy. These yield a likely coalescence rate of 100 per Myr per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 per Myr per MWEG to 1000 per Myr per MWEG. We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our Advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO-Virgo interferometers, with a plausible range between 0.0002 and 0.2 per year. The likely binary neutron-star detection rate for the Advanced LIGO-Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.

They have to find something or heads will roll...

[Michael Mozina]

Since I didn't design their equipment, I'm not entirely clear how often we should expect to unambiguously observe "gravity wave signals" over the course of a year...

When they begged for the $200m upgrade it was expected to detect on average about 40 events per year with potential for up to 400 per year.

http://arxiv.org/abs/1003.2480

We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the Initial and Advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters, and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our Galaxy. These yield a likely coalescence rate of 100 per Myr per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 per Myr per MWEG to 1000 per Myr per MWEG. We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our Advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO-Virgo interferometers, with a plausible range between 0.0002 and 0.2 per year. The likely binary neutron-star detection rate for the Advanced LIGO-Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.

They have to find something or heads will roll...

IMO the LIGO team pretty much backed themselves into a scientific corner. By claiming the 'discovery' of gravity waves without any actual visual confirmation, they've simply "assumed" the source, they haven't actually demonstrated it. If it turns out that their assumptions about overriding the original veto were simply wrong, and the original "veto" was a valid veto, those "blip transients" won't be something they can ever hope to verify visually/celestially. It's a quite a pickle they've gotten themselves into actually. I'd say they're stuck between a scientific rock and a hard place.

Que the Jeopardy theme song....

[Zyxzevn]

LIGO Press Conference, Wed 15th June, 10:15 PDT:
"LIGO project are planning to present some new results."

I wonder if their "new results" will match the recent solar storms.

[Michael Mozina]

LIGO Press Conference, Wed 15th June, 10:15 PDT:
"LIGO project are planning to present some new results."

I wonder if their "new results" will match the recent solar storms.

I really hope this isn't another "invisible" event.

[Zyxzevn]

It may be related to this report (behind paywall).
http://journals.aps.org/prl/abstract/10 ... 116.241102

It is another chirp.
If you look closely at the last figure (6), you can see that the signal start in the same phase,
but as the chirp ends, the phase does not match up again.
The first signal that LIGO found has exactly the same problem.
The change in phase means that the source of the signal was moving.
Which is likely with an electrical signal, or
a bombardment of charged particles (from the sun for example).

[willendure]

It may be related to this report (behind paywall).
http://journals.aps.org/prl/abstract/10 ... 116.241102

It is another chirp.
If you look closely at the last figure (6), you can see that the signal start in the same phase,
but as the chirp ends, the phase does not match up again.
The first signal that LIGO found has exactly the same problem.
The change in phase means that the source of the signal was moving.
Which is likely with an electrical signal, or
a bombardment of charged particles (from the sun for example).

Can you estimate how fast the source was moving to produce that phase shift in that time? It should be possible from that to work out the angular velocity of the source, no? Then from an upper bound of the speed of light, we can figure out the maximum distance the the source could be from the Earth. We can also get an idea of how fast the source would be moving if it was an electrical event in the upper atmosphere.

[Zyxzevn]

It may be related to this report (behind paywall).
http://journals.aps.org/prl/abstract/10 ... 116.241102

Sorry, it refers to the old chirp signal at 15 Sept, 2015.

The phase-change is still there.
First the top one is 0.1 ms behind the bottom one.
Just before the main signal, the top one is 0.1 ms in front.
And the signal ends with the top one even more in front (0.15 ms).
This corresponds to signal moving towards the detector in the top.
The amplitude difference can be caused by the different directions of the detectors.

The press conference is at:
https://iframe.dacast.com/b/59062/c/268750
15th June 10:15 PDT

The new LIGO info will appear in the Astronomy Picture of the Day at 1:30 pm EDT
http://apod.nasa.gov/apod/astropix.html

[Zyxzevn]

This is the new paper:
http://journals.aps.org/prl/pdf/10.1103 ... 116.241103

It is a signal on 26 dec 2015.

Again a signal in the frequency range of the electrical grid and air-conditioning, and sprites.
The signal is very noisy compared to the previous one. There seems to be so much noise,
that I think that they might find the voice of Einstein in the data as well.
I can't see what timing problems there are in this one. Too little data.

Events on the sun on: 25 and 26.
There were sun diving comets again.
Moderate solar flare.
Some earthquakes.

[Michael Mozina]

LIGO Press Conference, Wed 15th June, 10:15 PDT:
"LIGO project are planning to present some new results."

I wonder if their "new results" will match the recent solar storms.

I really hope this isn't another "invisible" event.

Thanks for the link to the new paper.



It was bad enough when visual observations in the sky were being routinely used to postulate the existence of invisible stuff in space and on Earth. We blew billions of dollars looking for 'dark matter' based on observations from space to no avail. Now we have subjective observations here on Earth that are being used to make claims about distant discoveries in "space" which cannot be seen by telescopes on Earth.

[Zyxzevn]

This is a article by ArsTechnica that is easier to read

[Zyxzevn]

Respond from LIGO researcher..
"Our data is filled with glitches (one the order of 1 per 10 seconds). Without detecting [the signal] in both detectors there is no evidence that it is not a glitch."

[comingfrom]

Gravitational waves: Scientists detect second 'fantastically significant' signal

The cataclysmic collision of black holes is a frequent occurrence in space, according to a team of international scientists that has just detected gravitational waves for the second time in history.

[willendure]

http://www.bbc.co.uk/news/science-environment-36540254

"Significantly for this detection, the new waves had an amplitude that was below the LIGO instruments' noise level, meaning sophisticated algorithms were required to pull out the signal."

Lol.

Pulling out the signal, like a magician pulling a rabbit from a hat.

[Zyxzevn]

First the top one is 0.1 ms behind the bottom one.
Just before the main signal, the top one is 0.1 ms in front.

Sorry, Pfff. Making this mistake again.
The phase difference is 100 larger. It is 10 ms instead of 0.1 ms.

[Cargo]

And the blackholes are getting even smaller now. Much like their creditability.