observing of collapsing binar systems

Joachim Schmidt
Joachim Schmidt
Joined: 19 Feb 05
Posts: 35
Credit: 391050
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Topic 190054

Hi,
are the interferometers already sensitive enough to observe the gravitational waves from collapsin binar system when both stars collide?
greets

Chipper Q
Chipper Q
Joined: 20 Feb 05
Posts: 1540
Credit: 708571
RAC: 0

observing of collapsing binar systems

Hi, Joachim - I believe they are, but I think the chances of detecting GWs from a spinning pulsar are better, since there's likely more spinning pulsars in the sky than binary inspiral (merger) events taking place at any given moment. The duration of the data set is also important – the upcoming S5 run will collect data for a whole year, greatly increasing the chances of detection of a particular event in a specific location... But yes, the detectors have already been used to place limits on such things as the stochastic background, and merger events in our Milky Way's halo... Also see the “Science Information and Progress Reports” section of the E@H main page for the first report on the S3 analysis... (Hopefully others will have better answers)

Chipper Q
Chipper Q
Joined: 20 Feb 05
Posts: 1540
Credit: 708571
RAC: 0

Uh, Joachim, I just found an

Uh, Joachim, I just found an abstract (General Relativity and Quantum Cosmology) saying that, “The combination of detector sensitivity, signal strength, and source density and distribution all point to binary inspiral as the most likely candidate for observation among all the anticipated sources of gravitational radiation for LIGO/VIRGO.” So I may be wrong about the most likely candidate being a pulsar, but the abstract is dated 10 Mar 1994, so hopefully a project moderator/developer can clarify this...

barkster
barkster
Joined: 3 Apr 05
Posts: 71
Credit: 447475
RAC: 0

If I recall from some of the

If I recall from some of the online lectures and other threads...

In both cases, it depends on the frequency of GWs being generated. Pulsars being constant freq, and binaries slowly increasing in freq to a final crescendo or "chirp". LIGO is most sensitive at a (relatively speaking) mid-to-high frequency range. But also, the binary inspiral would put out a "stronger" (higher amplitude) signal in the last few moments of in-spiral (due to greater mass/acceleration?) than a single pulsar (unless perhaps the pulsar had a large asymetry?).

Problem is, as noted below, the number of fast spinning pulsars (with constant, but "weak", GW radiation at a frequency within LIGO sensitivity) far outnumber the likelihood of binary in-spirals with a strong but fleeting detectable presence.

In other words, I think the LIGO team is betting that they will improve the sensitivy of the sensor enough to detect the "weaker" pulsars before any binary in-spiral gives them an opportunity to observe the finale.

"No, I'm not a scientist... but I did stay at a Holiday Inn Express."

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