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>> With the still lacking independent confirmation that LIGO sees events of astrophysical origin > False. GW170817. One observation does not independent confi

>> With the still lacking independent confirmation that LIGO sees events of astrophysical origin > False. GW170817. One observation does not independent confirmation make. Obviously from context Sabine doesn't mean independent in the independent group sense as the observation itself is collaborative and there aren't exactly other ligos around. Why are you so defensive?

tobinfricke 7y ago
I took that sentence to mean "independent" as in having some confirmation other than the gravitational wave signal. That's provided by the optical observations of GW170817 which confirm independently that the event is real. > there aren't exactly other ligos around One of the three currently operating GW detectors is Virgo, of a different design and build by different people, in Italy. It's true that LIGO and Virgo collaborate extensively.
- dnautics 7y ago
  For reference here are the data for the so far, only reported collaboratively observed incident: https://commons.m.wikimedia.org/wiki/File:GW170814_signal.png#mw-jump-to-license https://commons.m.wikimedia.org/wiki/File:GW170814_signal.pn... While I'm not a signals expert... I'm not exactly convinced.
  - tobinfricke 7y ago
    There is a lot more data than simply that figure on Wikipedia. For example, you may download all of the raw gravitational wave strain data and re-analyze it yourself if you felt so inclined. The LIGO community has done an amazing job with the "open science center" that releases both the timeseries data and tools useful in processing it. https://www.gw-openscience.org/about/ https://www.gw-openscience.org/about/ There are eleven peer-reviewed published papers on this event, in addition to a complete public release of the time series data. https://www.ligo.caltech.edu/page/detection-companion-papers https://www.ligo.caltech.edu/page/detection-companion-papers
throwaway2048 7y ago
The chance of a spurious signal from the direction, distance and magnitude GW170817 lining up with telescope observations by random chance is absolutely astronomically tiny.
- dnautics 7y ago
  let's say a "telescope observation" has to be on the order of a supernova explosion to be observable. There are about 30 supernova explosions per second in the observable universe. To date about 10,000 supernovas have been observed using EM spectra, on average that's about one observed major astronomical event every other day.
  - SiempreViernes 7y ago
    GRB170817A isn't a supernova though, so the SNe rate is irrelevant. First estimate of kilonova rates I found online is one per day per Gpc, and with your absurd extrapolation to the entire observable universe you get one per hour in one of the 40 000 degrees^2 of the entire sky.
    - dnautics 7y ago
      You can't assume GRB170817A isn't a supernova because there is an associated GW170817A; that's begging the question.
      - throwaway2048 7y ago
        LIGO doesn't detect supernovas, so its irrelevant
      - SiempreViernes 7y ago
        Why do you think I'm assuming the type of the most well studied optical transient we've had this century? This is a source that was observed by something like a hundred different teams. I'm ruling out a SN origin on the basis of the (at least) dozen of direct observations that show it isn't.

tobinfricke 7y ago

I took that sentence to mean "independent" as in having some confirmation other than the gravitational wave signal. That's provided by the optical observations of GW170817 which confirm independently that the event is real. > there aren't exactly other ligos around One of the three currently operating GW detectors is Virgo, of a different design and build by different people, in Italy. It's true that LIGO and Virgo collaborate extensively.

dnautics 7y ago
For reference here are the data for the so far, only reported collaboratively observed incident: https://commons.m.wikimedia.org/wiki/File:GW170814_signal.png#mw-jump-to-license https://commons.m.wikimedia.org/wiki/File:GW170814_signal.pn... While I'm not a signals expert... I'm not exactly convinced.
- tobinfricke 7y ago
  There is a lot more data than simply that figure on Wikipedia. For example, you may download all of the raw gravitational wave strain data and re-analyze it yourself if you felt so inclined. The LIGO community has done an amazing job with the "open science center" that releases both the timeseries data and tools useful in processing it. https://www.gw-openscience.org/about/ https://www.gw-openscience.org/about/ There are eleven peer-reviewed published papers on this event, in addition to a complete public release of the time series data. https://www.ligo.caltech.edu/page/detection-companion-papers https://www.ligo.caltech.edu/page/detection-companion-papers

throwaway2048 7y ago

The chance of a spurious signal from the direction, distance and magnitude GW170817 lining up with telescope observations by random chance is absolutely astronomically tiny.

dnautics 7y ago
let's say a "telescope observation" has to be on the order of a supernova explosion to be observable. There are about 30 supernova explosions per second in the observable universe. To date about 10,000 supernovas have been observed using EM spectra, on average that's about one observed major astronomical event every other day.
- SiempreViernes 7y ago
  GRB170817A isn't a supernova though, so the SNe rate is irrelevant. First estimate of kilonova rates I found online is one per day per Gpc, and with your absurd extrapolation to the entire observable universe you get one per hour in one of the 40 000 degrees^2 of the entire sky.
  - dnautics 7y ago
    You can't assume GRB170817A isn't a supernova because there is an associated GW170817A; that's begging the question.
    - throwaway2048 7y ago
      LIGO doesn't detect supernovas, so its irrelevant
    - SiempreViernes 7y ago
      Why do you think I'm assuming the type of the most well studied optical transient we've had this century? This is a source that was observed by something like a hundred different teams. I'm ruling out a SN origin on the basis of the (at least) dozen of direct observations that show it isn't.