From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Thu May 22 2003 - 09:02:32 PDT
On Thu, May 22, 2003 at 08:27:55AM -0700, Greg Aldering wrote:
> One thing that would make this issue more robust is if we had done a
> fit with alpha=0 and could say the cosmology wasn't much affected.
OK, I just did that. (Once I managed to get my fits running on PDSF,
it's possible to do some of them quickly if the jobs don't get backed
up. It still takes a while to redo everything, more from the
administration of keeping track of it all, although the CPU time gets
non-negligible.)
The OM_flat is basically identical; the contours *do* slide along their
major axis up and to the right, though. (See attached postscript.)
Script-M is slightly different (goes from -3.48+-.05 to -3.45+-0.05),
which is probably just due to the mean stretch of the low-z sample not
being 1.0. The chisquare gets quite a bit worse, which is unsurprising
given that the best-fit value of alpha was several sigma away from 0.
This is enough for us to say honestly that the cosmology is not affected
my if you do a fit without alpha. (The shift along the major axis is
smaller than the "fit method" systematic we're already using.) Where
should that sentence go into the paper? It probably depends on whether
or not we leave in the stretch/luminosity figure.
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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