From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Wed May 14 2003 - 08:25:15 PDT
On Tue, May 13, 2003 at 11:15:03AM -0700, Greg Aldering wrote:
> a) Follow Phillips 1999 in throwing out very red objects even though
> you are going to extinction correct. I believe that Phillips
> threw-out objects with Bmax-Vmax > 0.2 mag. (Talk about dirty
> laundry!)
It's not clear to me that he did this when finding his RB values. He
did do that for a bunch of the analysis, but for the RB stuff
specifically he only talks about throwing out the SNe without a point
near max. I believe that his value *is* with the most reddened SNe (he
certainly plots those), and as such throwing out the most reddened SNe
from our set isn't a matter of saying "just as Phillips"....
If we don't throw out the reddest ones, we have the situation at:
http://brahms.phy.vanderbilt.edu/~rknop/scp/hst/#rv254
with the w problem. (This is a problem not because "w is too low", but
because I really do believe that some of these SNe are being hugely
overcorrected for extinction, and the lower RB probably is more right.)
Another possibility is to throw out >2sigma outliers from the extinction
corrected fit. That eliminates 92bs, 95bd, 96bo, and 9855. The latter
three of these are the "most red"; 92bs has an unremarkable color
(EBV=-0.037+-0.022). This is cleaner, I belive, since it's a
well-defined cut. The only problem is that out of 79 SNe, you'd expect
there to be 4 supernovae which are >2sigma outliers. (Of course, three
of those are >2.5sigma-- all but 9855-- and you'd only expect one.)
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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