Astronomy:Hubble–Reynolds law
The Hubble–Reynolds law models the surface brightness of elliptical galaxies as
- [math]\displaystyle{ I(R) = \frac{I_0}{(1+R/R_H)^2} }[/math]
Where [math]\displaystyle{ I(R) }[/math] is the surface brightness at radius [math]\displaystyle{ R }[/math], [math]\displaystyle{ I_0 }[/math] is the central brightness, and [math]\displaystyle{ R_H }[/math] is the radius at which the surface brightness is diminished by a factor of 1/4. It is asymptotically similar to the De Vaucouleurs' law which is a special case of the Sersic profile for elliptical galaxies.[1]
The law is named for the astronomers Edwin Hubble and John Henry Reynolds. It was first formulated by Reynolds in 1913[2] from his observations of galaxies (then still known as nebulae). It was later re-derived by Hubble in 1930[3] specifically in observations of elliptical galaxies.
References
- ↑ Binney & Tremaine. Galactic Dynamics 2008.
- ↑ Reynolds, J. H. (12 December 1913). "The Light Curve of the Andromeda Nebula (N.G.C. 224)". Monthly Notices of the Royal Astronomical Society 74 (2): 132–136. doi:10.1093/mnras/74.2.132. Bibcode: 1913MNRAS..74..132R.
- ↑ Hubble, E. P. (May 1930). "Distribution of luminosity in elliptical nebulae.". The Astrophysical Journal 71: 231. doi:10.1086/143250. Bibcode: 1930ApJ....71..231H.
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