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SNe Ia data - photon flux or energy flux?
Is modern distance modulus vs redshift data from type Ia supernovae
based on photon flux, so that the expansion of space would cause a 1/(z+1) decrease in the flux, or is it based on energy flux, in which case the expansion of space would cause a 1/((z+1)^2) diminution? -- Bob Day |
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SNe Ia data - photon flux or energy flux?
Bob Day wrote:
Is modern distance modulus vs redshift data from type Ia supernovae based on photon flux, so that the expansion of space would cause a 1/(z+1) decrease in the flux, or is it based on energy flux, in which case the expansion of space would cause a 1/((z+1)^2) diminution? Most measurements these days in the optical and near-IR are made with detectors which count photons, not energy. What people do with the measurements afterwards is very hard to follow properly. Michael Richmond |
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SNe Ia data - photon flux or energy flux?
In article , "Bob Day"
writes: Is modern distance modulus vs redshift data from type Ia supernovae based on photon flux, so that the expansion of space would cause a 1/(z+1) decrease in the flux, or is it based on energy flux, in which case the expansion of space would cause a 1/((z+1)^2) diminution? Energy. |
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SNe Ia data - photon flux or energy flux?
In article ,
"Stupendous_Man" writes: Bob Day wrote: Is modern distance modulus vs redshift data from type Ia supernovae based on photon flux, so that the expansion of space would cause a 1/(z+1) decrease in the flux, or is it based on energy flux, in which case the expansion of space would cause a 1/((z+1)^2) diminution? Most measurements these days in the optical and near-IR are made with detectors which count photons, not energy. Yes. But the raw measurements are converted. What people do with the measurements afterwards is very hard to follow properly. You need K-corrections etc. Standard stuff. The 1/((z+1)^2) factor is for a K-correction of 0. |
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