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Measuring black hole red shifting?

  1. Nov 27, 2014 #1
    I've been searching over this and I don't quite get it yet. I just heard about this "z" parameter for gravitational red shifting and I thought it'd be fun to apply into the scenario of a solar-mass black hole.
    The equation I looked at was (1/(2GM/c^2r)^0.5) - 1 = z
    So, like, does the z parameter just mean that you multiply the original wavelength by it or add it with the original wavelength? Does the z give you a shift in nanometers or meters? I'd really appreciate it if someone could give me a good understanding of this.
  2. jcsd
  3. Nov 27, 2014 #2


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    z is usually defined as ##z=\frac{\lambda_o-\lambda_e}{\lambda_e}=\frac{\lambda_o}{\lambda_e}-1## where ##\lambda_e## is the emitted wavelength and ##\lambda_o## is the observed wavelength.
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