Monday, August 26, 2013

Fitting the Tully-Fisher relation

There's one thing I can't quite wrap my head around while reading literature on the Tully-Fisher relation: why is the fitting always performed in the magnitude-log(velocity) space? It may be easier to fit an expression y = mx + b to data than y = c*x**z, but one would have to deal with asymmetric errors in two dimensions.
I'm currently trying to figure out a way to do the fit in semi-log space, namely, magnitude-velocity space, using errors in both directions and MCMC.

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