Need help with some calculations with gravitational waves

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Discussion Overview

The discussion revolves around the calculations involved in the first discovery of gravitational waves, specifically focusing on the methods used to determine the masses of merging black holes, the energy radiated in gravitational waves, and the distance of the event from Earth. The inquiry includes aspects of theoretical and mathematical reasoning related to gravitational wave detection.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that the "chirp mass" is calculated from the frequency and rate of change of frequency, which helps determine the basic mass scale of the black holes involved in the merger.
  • Another participant mentions that numerical modeling based on General Relativity is used to recreate the waveform shape to estimate the individual masses of the black holes.
  • It is proposed that the energy radiated away is estimated using General Relativity, based on a model of the merger and the identified masses.
  • One participant indicates that the amplitude of the gravitational wave signal is compared with theoretical amplitudes to estimate the distance of the event.
  • A question is raised about the angle between the orbital plane of the binary black holes and the direction to Earth, indicating a further area of inquiry.
  • A later paper is referenced, which may contain more detailed information regarding the binary black hole merger.

Areas of Agreement / Disagreement

The discussion includes multiple viewpoints regarding the calculations and methods used, with no consensus reached on the accuracy of the proposed methods or the specific formulas involved.

Contextual Notes

Participants express uncertainty about the correctness of the proposed methods and calculations, and there are references to specific papers that may provide additional context or detail.

Meerio
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I have some questions about the first discovery paper that was released about gravitational waves, especially some of the maths.

How did they:
1. Calculate the masses of the black holes that merged
2. Calculate the energy radiated away in gravitational waves
3. Calculate how far away the event happened

(I assume the third can be calculated with a formula that involves amplitude, but I am yet to find the right formula's for any of these)

Sorry if this is easily solvible but I couldn't find the answers myself.

Paper: https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102
 
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I think this is probably how it was done:
1. As mentioned in the paper, the frequency and rate of change of frequency determine the "chirp mass" which gives the basic mass scale. Numeric modelling based on General Relativity with varying parameters is used to recreate the shape of the wave form in figure 2 to give the likely individual masses.
2. The radiated energy is estimated using General Relativity from a model of the merger given the identified masses.
3. The amplitude of the signal is compared with the theoretical amplitude at a given distance for that amount of energy to establish the approximate distance.
 
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Thank you very much if anyone knows whether this is true or not please confirm!
 
What is the angle between the orbital plane of the binary hole, and the direction to Earth?
 

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