"O1Spot1" Continuous Gravitational Wave Galactic Center search started

Mad_Max
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Yes, i know about primary

Mike Hewson wrote:

For the LIGO detectors about 10 Hz to a few thousand Hz is the quoted dynamic range. Reception lower than that is dominated by effects related to being on a planet, higher than that is largely a matter of optics. However the 'sweet spot' with maximal sensitivity is about 200 hz. As demonstrated inspiralling binary systems don't last very long in that band ! 'Continuous' for E@H purposes may be defined as having a low rate of change of frequency and thus remaining sufficiently coherent over long integration times when we 'fold' a recorded signal to catch a candidate waveform. If the frequency changes too much the ( Fourier ) transform will have a lower peak and won't reach sufficient signal-to-noise to trigger the detection statistic threshold. In general LIGO likes a five sigma result or better to claim a discovery.

Cheers, Mike.

Yes, i know about primary frequency range and 'sweet spot' of LIGO. I saw it's sensitivity profile  graphs (sensitivity vs frequency) some time ago. But LIGO does not hard limited to this frequency range. Just sensitivity gets lower and signal/noise gets worse as you move further from 'sweet spot'. No any fixed wall/cut-off.

AFAIR at 1 Hz it is about a few hundreds times less sensitivity vs 100-200 Hz. So it is not possible to catch a single merger event with such low sensitivity (unless it is very close to our own galaxy - but this is very unlikely / rare ) at low frequencies. This is a reason why  frequencies < 10 Hz usually considered as not usable at all and containing no useful information (only noise).

But if we are talking about stable continuous waves from long lived binaries where we can accurately integrate many thousands orbital periods with practically unchanged wave form may be it is still possible to reach signal/noise gain at computation stage big enough to outweigh loss of S/N at detectors itself?

Mike Hewson
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Mad_Max wrote:But if we are

Mad_Max wrote:
But if we are talking about stable continuous waves from long lived binaries where we can accurately integrate many thousands orbital periods with practically unchanged wave form may be it is still possible to reach signal/noise gain at computation stage big enough to outweigh loss of S/N at detectors itself?

Long lived binaries will have periods well under 10Hz. But for earthside detections of other continuous wave possibilities see this very recent LIGO paper on exactly that : Status Of The Continuous Gravitational Wave Searches In The Advanced Detector Era 

Cheers, Mike.

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

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

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The Wallet is unlocked, what

The Wallet is unlocked, what can i do to change this?

Client Messages: No coins to stake; Unable To Send Beacon! Unlock Wallet!

Bernd Machenschalk
Bernd Machenschalk
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But if we are talking about

But if we are talking about stable continuous waves from long lived binaries where we can accurately integrate many thousands orbital periods with practically unchanged wave form may be it is still possible to reach signal/noise gain at computation stage big enough to outweigh loss of S/N at detectors itself?

There is an old blog post from Amber (LivingLIGO) about low-frequency GWs at https://stuver.blogspot.de/2012/05/q-why-isnt-ligo-sensitive-to-gw-from.html . The sensitivity curves aren't recent, but the shape is still valid. Below somewhere between 10-15Hz the curve rises steep enough to show that the for every 1-2Hz the sensitivity drops by an order of magnitude. IOW for every 2Hz below 10Hz you'd have to integrate over 10x as much data to get the same SNR.

BM

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