Freeman law

The Freeman law is a statement in astronomy which says that disk galaxies have the same surface brightness, Σ at the center. It was described in 1970 by Ken Freeman.[1]

The Freeman law was confirmed in year 2010 for a sample of 30000 Sloan Digital Sky Survey galaxy images [2] and it can be used with the Tully-Fisher relation to determine the luminosity and therefore distance of an observed galaxy.

However more recently it has been argued that the Freeman law is an effect of selection bias.[1][3]

References

  1. 1 2 McGaugh et al., "Galaxy Selection and Surface Brightness Distribution" (1995) Astronomical Journal, 110 (1995) 573,
  2. ↑ Kambiz Fathi, "Revisiting the Freeman Law in the Local Universe" (2010) Astrophysical Journal, 722 (2010) L120,
  3. ↑ Minnesota State University, ""


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