From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Tue Apr 22 2003 - 11:00:19 PDT
On Tue, Apr 22, 2003 at 09:50:06AM -0700, Alex Conley wrote:
> This is something you are probably already aware of, but I thought
> it was worth pointing out: Another difference between the way
> we do analysis and the way the Hi-z team does analysis is that
> they effectively fix alpha from low redshift SNe and then use that
> for all objects, while we include alpha as a nuisance parameter in
> our full fit.
>
> Of course, since they don't use stretch, they aren't really using alpha,
> but MLCS uses a correction delta which is based on a training set of low-z
> SNe, and in Riess 98 they use a delta_m15 correction with a slope fixed by
> Phillips 98, which is a low-z sample.
>
> Do we have any idea what this does to the fit contours?
I have no idea, and I'm not really worried about it. Since we're not
using their method, there's no need to worry too much about what that
method does. When I do the combined fits, I use their "template
fitting" results rather than their MLCS results, since the template
fitting ones should be closer to our method. (Though, as I note in the
cautionary text, even there there are differences in how the lightcurves
were handled, so it's not one big consistent data set.)
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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